6
6.0
Jun 29, 2018
06/18
by
Victoria M. Kaspi; Michael Kramer
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Radio pulsars are unique laboratories for a wide range of physics and astrophysics. Understanding how they are created, how they evolve and where we find them in the Galaxy, with or without binary companions, is highly constraining of theories of stellar and binary evolution. Pulsars' relationship with a recently discovered variety of apparently different classes of neutron stars is an interesting modern astrophysical puzzle which we consider in Part I of this review. Radio pulsars are also...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1602.07738
3
3.0
Jun 29, 2018
06/18
by
L. Saha; V. R. Chitnis; A. Shukla; A. R. Rao; B. S. Acharya
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We study the characteristics of the TeV binary LS I +61$^\circ$ 303 in radio, soft X-ray, hard X-ray, and gamma-ray (GeV and TeV) energies. The long term variability characteristics are examined as a function of the phase of the binary period of 26.496 days as well as the phase of the super orbital period of 1626 days, dividing the observations into a matrix of 10$\times$10 phases of these two periods. It is found that the long term variability can be described by a sine function of the super...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1603.09109
6
6.0
Jun 29, 2018
06/18
by
A. Marcowith; A. Bret; A. Bykov; M. E. Dieckman; L. O. C. Drury; B. Lembege; M. Lemoine; G. Morlino; G. Murphy; G. Pelletier; I. Plotnikov; B. Reville; M. Riquelme; L. Sironi; A. Stockem Novo
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Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebul\ae, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1604.00318
3
3.0
Jun 29, 2018
06/18
by
Oliver Q. Hamil; Nick J. Stone; Jirina R. Stone
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The magnetic dipole radiation (MDR) model is currently the best approach we have to explain pulsar radiation. However a most characteristic parameter of the observed radiation, the braking index n$_{\rm obs}$ shows deviations for all the eight best studied isolated pulsars, from the simple model prediction n$_{\rm dip}$ = 3. The index depends upon the rotational frequency and its first and second time derivatives, but also on the assumption of that the magnetic dipole moment and inclination...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1608.01375
3
3.0
Jun 29, 2018
06/18
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Ryo Mikami; Katsuaki Asano; Shuta J. Tanaka; Shota Kisaka; Mamoru Sekido; Kazuhiro Takefuji; Hiroshi Takeuchi; Hiroaki Misawa; Fuminori Tsuchiya; Hajime Kita; Yoshinori Yonekura; Toshio Terasawa
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We present the results of the simultaneous observation of the giant radio pulses (GRPs) from the Crab pulsar at 0.3, 1.6, 2.2, 6.7, and 8.4 GHz with four telescopes in Japan. We obtain 3194 and 272 GRPs occurring at the main pulse and the interpulse phases, respectively. A few GRPs detected at both 0.3 and 8.4 GHz are the most wide-band samples ever reported. In the frequency range from 0.3 to 2.2 GHz, we find that about 70\% or more of the GRP spectra are consistent with single power laws and...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1608.07673
4
4.0
Jun 29, 2018
06/18
by
D. Onic; D. Urosevic; D. Leahy
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Recent observations of the microwave sky, by the space telescopes such as WMAP and Planck, have opened a new window into the analysis of continuum emission from supernova remnants (SNRs). In this paper, different emission models that can explain the characteristic shape of presently known integrated radio/microwave continuum spectrum of the Galactic SNR IC 443 are tested and discussed. In particular, the possibility that the slight bump in the integrated continuum of this remnant around 20 --...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1611.08745
3
3.0
Jun 30, 2018
06/18
by
M. Miceli; F. Acero; G. Dubner; A. Decourchelle; S. Orlando; F. Bocchino
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The supernova remnant SN 1006 is a powerful source of high-energy particles and evolves in a relatively tenuous and uniform environment, though interacting with an atomic cloud in its northwestern limb. The X-ray image of SN 1006 reveals an indentation in the southwestern part of the shock front and the HI maps show an isolated cloud (southwestern cloud) having the same velocity as the northwestern cloud and whose morphology fits perfectly in the indentation. We performed spatially resolved...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.7196
4
4.0
Jun 30, 2018
06/18
by
Diego F. Torres; Analía Cillis; Jonatan Martín; Emma de Oña Wilhelmi
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The increasing sensitivity of instruments at X-ray and TeV energies have revealed a large number of nebulae associated with bright pulsars. Despite this large data set, the observed pulsar wind nebulae (PWNe) do not show a uniform behavior and the main parameters driving features like luminosity, magnetization, and others are still not fully understood. To evaluate the possible existence of common evolutive trends and to link the characteristics of the nebula emission with those of the powering...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.5485
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5.0
Jun 30, 2018
06/18
by
Rubens C. Reis; Mark T. Reynolds; Jon M. Miller; Dominic J. Walton
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The co-evolution of a supermassive black hole with its host galaxy through cosmic time is encoded in its spin. At $z>2$, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. However, it is unknown whether below $z\sim1$ these black holes continue to grow via coherent accretion or in a chaotic manner, though clear differences are predicted in their spin evolution. An established method to measure the spin of black holes is via the study of...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.4973
4
4.0
Jun 30, 2018
06/18
by
Aru Beri; Chetana Jain; Biswajit Paul; Harsha Raichur
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We review the pulse profile evolution of the unique accretion powered X-ray pulsar 4U 1626-67 over the last 40 years since its discovery. This pulsar showed two distinct eras of steady spin-up separated by a steady spin-down episode for about 18 years. In the present work, using data from different observatories active during each phase of spin-up and spin-down we establish a clear correlation between the accretion torque acting on this pulsar and its pulse profile. The energy resolved pulse...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.2936
3
3.0
Jun 30, 2018
06/18
by
R. Hascoet; A. M. Beloborodov; P. R. den Hartog
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We test a model recently proposed for the persistent hard X-ray emission from magnetars. In the model, hard X-rays are produced by a decelerating electron-positron flow in the closed magnetosphere. The flow decelerates as it radiates its energy away via resonant scattering of soft X-rays, then it reaches the top of the magnetic loop and annihilates there. We test the model against observations of three magnetars: 4U 0142+61, 1RXS J1708-4009, and 1E 1841-045. We find that the model successfully...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.3406
6
6.0
Jun 30, 2018
06/18
by
S. Adrián-Martínez; A. Albert; M. André; M. Anghinolfi; G. Anton; M. Ardid; T. Astraatmadja; J. -J. Aubert; B. Baret; J. Barrios; S. Basa; E. Nezri; D. Palioselitis; G. E. Păvălaş; C. Perrina; P. Piattelli; V. Popa; T. Pradier; C. Racca; G. Riccobene; R. Richter; V. Bertin; C. Rivière; A. Robert; K. Roensch; A. Rostovtsev; M. Saldaña; D. F. E. Samtleben; A. Sánchez-Losa; M. Sanguineti; P. Sapienza; J. Schmid; S. Biagi; J. Schnabel; S. Schulte; F. Schüssler; T. Seitz; C. Sieger; A....
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Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.1600
3
3.0
Jun 30, 2018
06/18
by
Partha Sarathi Pal; Sandip K. Chakrabarti
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The Temporal and Spectral variations of black hole candidates during outbursts have been reported in several publications. It is well known that during an outburst, the source becomes soft in the first few days, and then returns to the hard state after a few weeks or months. In the present paper, we show the variation of Comptonization Efficiency (CE), obtained from the ratio of the black body photon number to the power-law photon number, as a function of time in several outbursts. Since the...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.4772
4
4.0
Jun 30, 2018
06/18
by
Nissim Fraija
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A high-energy component in the radio galaxy Centaurus A was reported after analyzing four years of Fermi data. The spectrum of this component is described by means of a broken power law with a break energy of 4 GeV and, below and above spectral indices of $\alpha_1$=2.74$\pm$0.03 and $\alpha_2$=2.09$\pm$0.20, respectively. Also a faint $\gamma$-ray flux at TeV energies was detected by H.E.S.S.. In this paper we show that the spectrum at GeV-TeV energies is described through synchrotron...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.4558
4
4.0
Jun 30, 2018
06/18
by
Katsuaki Asano; Peter Meszaros
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We revisit the neutrino and ultra high-energy cosmic ray (UHECR) production from gamma-ray bursts (GRBs) with time-dependent simulations for the proton-induced cascades. This method can generate self-consistent photon, neutrino and escaped neutron spectra. To obtain the integrated background spectra, we take into account the distributions of the burst luminosity and pulse duration timescale. A benchmark case with standard GRB luminosity function, a bulk Lorentz factor $\Gamma=300$ and a proton...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.6057
5
5.0
Jun 30, 2018
06/18
by
A. D'Aì; R. Iaria; T. Di Salvo; A. Riggio; L. Burderi; N. R. Robba
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The source GX 13+1 is a persistent, bright Galactic X-ray binary hosting an accreting neutron star. It shows highly ionized absorption features, with a blueshift of $\sim$ 400 km s$^{-1}$ and an outflow-mass rate similar to the accretion rate. Many other X-ray sources exhibit warm absorption features, and they all show periodic dipping behavior at the same time. Recently, a dipping periodicity has also been determined for GX 13+1 using long-term X-ray folded light-curves, leading to a clear...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.0071
6
6.0
Jun 30, 2018
06/18
by
V. M. Kaspi; R. F. Archibald; V. Bhalerao; F. Dufour; E. V. Gotthelf; H. An; M. Bachetti; A. M. Beloborodov; S. E. Boggs; F. E. Christensen; W. W. Craig; B. W. Grefenstette; C. J. Hailey; F. A. Harrison; J. A. Kennea; C. Kouveliotou; K. K. Madsen; K. Mori; C. B. Markwardt; D. Stern; J. K. Vogel; W. W. Zhang
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We present the X-ray timing and spectral evolution of the Galactic Center magnetar SGR J1745-2900 for the first ~4 months post-discovery using data obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR)} and Swift observatories. Our timing analysis reveals a large increase in the magnetar spin-down rate by a factor of 2.60 +/- 0.07 over our data span. We further show that the change in spin evolution was likely coincident with a bright X-ray burst observed in 2013 June by Swift, and...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.5344
4
4.0
Jun 30, 2018
06/18
by
Odele Straub; Olivier Godet; Natalie Webb; Mathieu Servillat; Didier Barret
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In this paper we present a comprehensive study of the mass of the intermediate mass black hole candidate HLX-1 in the galaxy ESO 243-49. We analyse the continuum X-ray spectra collected by Swift, XMM-Newton, and Chandra with the slim disc model, SLIMBH, and estimate the black hole mass for the full range of inclination (inc = 0{\deg} - 85{\deg}) and spin (a* = 0 - 0.998). The relativistic SLIMBH model is particularly suited to study high luminosity disc spectra as it incorporates the effects of...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.6407
4
4.0
Jun 30, 2018
06/18
by
H. Avdan; S. Kayaci Avdan; A. Akyuz; S. Balman
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We report our findings on a new quasi-periodic oscillation (QPO) and a long period from the ultraluminous X-ray source (ULX) X-2 in nearby galaxy NGC 4736 based on the Chandra and XMM-Newton archival data. To examine the timing properties, power density spectra of the source have been obtained using Fast Fourier Transform. Also the spectral parameters of the source have been calculated by obtaining and fitting the energy spectra. Power density spectrum of this source reveals a QPO peak at...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.7034
4
4.0
Jun 30, 2018
06/18
by
Andrew Thornbury; Luke O'C. Drury
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We derive an analytic expression for the power transferred from interstellar turbulence to the Galactic cosmic rays in propagation models which include re-acceleration. This is used to estimate the power required in such models and the relative importance of the primary acceleration as against re-acceleration. The analysis provides a formal mathematical justification for Fermi's heuristic account of second order acceleration in his classic 1949 paper.
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1404.2104
6
6.0
Jun 30, 2018
06/18
by
Deepto Chakrabarty; John A. Tomsick; Brian W. Grefenstette; Dimitrios Psaltis; Matteo Bachetti; Didier Barret; Steven E. Boggs; Finn E. Christensen; William W. Craig; Felix Fuerst; Charles J. Hailey; Fiona A. Harrison; Victoria A. Kaspi; Jon M. Miller; Michael A. Nowak; Vikram Rana; Daniel Stern; Daniel R. Wik; Joern Wilms; William W. Zhang
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eye 6
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The low-mass X-ray binary Cen X-4 is the brightest and closest (
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1403.6751
3
3.0
Jun 30, 2018
06/18
by
R. Boissay; S. Paltani; G. Ponti; S. Bianchi; M. Cappi; J. S. Kaastra; P. -O. Petrucci; N. Arav; G. Branduardi-Raymont; E. Costantini; J. Ebrero; G. A. Kriss; M. Mehdipour; C. Pinto; K. C. Steenbrugge
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eye 3
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Active Galactic Nuclei (AGN) are the most luminous persistent objects in the universe. An excess of X-ray emission below about 2 keV, called soft-excess, is very common in Type 1 AGN spectra. The origin of this feature remains debated. Originally modeled with a blackbody, there are now several possibilities to model the soft-excess, including warm Comptonization and blurred ionized reflection. In this paper, we test ionized-reflection models on Mrk 509, a bright Seyfert 1 galaxy for which we...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1404.3863
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4.0
Jun 30, 2018
06/18
by
Drew Clausen; Steinn Sigurdsson; David F. Chernoff
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The discovery of a binary comprising a black hole (BH) and a millisecond pulsar (MSP) would yield insights into stellar evolution and facilitate exquisitely sensitive tests of general relativity. Globular clusters (GCs) are known to harbor large MSP populations and recent studies suggest that GCs may also retain a substantial population of stellar mass BHs. We modeled the formation of BH+MSP binaries in GCs through exchange interactions between binary and single stars. We found that in dense,...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1404.7502
5
5.0
Jun 30, 2018
06/18
by
Jianfu Zhang; Bing Xu; Jufu Lu
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We study the origin of non-thermal emissions from the Galactic black hole X-ray binary Cygnus X--1 which is a confirmed high mass microquasar. By analogy with those methods used in studies of active galactic nuclei, we propose a two-dimensional, time-dependent radiation model from the microquasar Cygnus X--1. In this model, the evolution equation for relativistic electrons in a conical jet are numerically solved by including escape, adiabatic and various radiative losses. The radiative...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1405.1138
5
5.0
Jun 28, 2018
06/18
by
M. De Pasquale; S. R. Oates; J. L. Racusin; D. A. Kann; B. Zhang; A. Pozanenko; A. A. Volnova; A. Trotter; N. Frank; A. Cucchiara; E. Troja; B. Sbarufatti; N. R. Butler; S. Schulze; Z. Cano; M. J. Page; A. J. Castro-Tirado; J. Gorosabel; A. Lien; O. Fox; O. Littlejohns; J. S. Bloom; J. X. Prochaska; J. A. de Diego; J. Gonzalez; M. G. Richer; C. Román-Zúñiga; A. M. Watson; N. Gehrels; H. Moseley; A. Kutyrev; S. Zane; V. Hoette; R. R. Russell; V. Rumyantsev; E. Klunko; O. Burkhonov; A. A....
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Gamma-ray bursts (GRBs) are the most luminous explosions in the universe, yet the nature and physical properties of their energy sources are far from understood. Very important clues, however, can be inferred by studying the afterglows of these events. We present optical and X-ray observations of GRB 130831A obtained by Swift, Chandra, Skynet, RATIR, Maidanak, ISON, NOT, LT and GTC. This burst shows a steep drop in the X-ray light-curve at $\simeq 10^5$ s after the trigger, with a power-law...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1509.09234
5
5.0
Jun 28, 2018
06/18
by
Matthew Kerr; Paul Ray; Simon Johnston; Ryan Shannon; Fernando Camilo
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We have constructed timing solutions for 81 gamma-ray pulsars covering more than five years of Fermi data. The sample includes 37 radio-quiet or radio-faint pulsars which cannot be timed with other telescopes. These timing solutions and the corresponding pulse times of arrival are prerequisites for further study, e.g. phase-resolved spectroscopy or searches for mode switches. Many gamma-ray pulsars are strongly affected by timing noise, and we present a new method for characterizing the noise...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1510.05099
3
3.0
Jun 28, 2018
06/18
by
N. Miller; S. Marka; I. Bartos
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The angular dependence of emission in gamma-ray bursts (GRB) is of fundamental importance in understanding the underlying physical mechanisms, as well as in multimessenger search efforts. We examine the prospects of using reconstructed GRB jet opening angles and off-axis observer angles in determining the jet structure. We show that the reconstructed angles by Ryan et al. (2015) are inconsistent with uniform jet structure. We further calculate the number of GRBs with accurately reconstructed...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1511.00706
3
3.0
Jun 28, 2018
06/18
by
Tong Liu; Li Xue; Xiao-Hong Zhao; Fu-Wen Zhang; Bing Zhang
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Black holes (BHs) hide themselves behind various astronomical phenomena, and their properties, i.e., mass and spin, are usually difficult to constrain. One leading candidate for the central engine model of gamma-ray bursts (GRBs) invokes a stellar mass BH and a neutrino-dominated accretion flow (NDAF), with the relativistic jet launched due to neutrino-anti-neutrino annihilations. Such a model gives rise to a matter-dominated fireball, and is suitable to interpret GRBs with a dominant thermal...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1511.02800
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3.0
Jun 28, 2018
06/18
by
Maria Massi; Guidetta Torricelli-Ciamponi
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One of the most unusual aspects of the X-ray binary LSI +61 303 is that at each orbit (P1=26.4960 \pm 0.0028 d) one radio outburst occurs whose amplitude is modulated with Plong, a long-term period of more than 4 yr. It is still not clear whether the compact object of the system or the companion Be star is responsible for the long-term modulation. We study here the stability of Plong. Such a stability is expected if Plong is due to periodic (P2) Doppler boosting of periodic (P1) ejections from...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1511.05621
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4.0
Jun 29, 2018
06/18
by
E. Rivers; M. Brightman; S. Bianchi; G. Matt; K. Nandra; Y. Ueda
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An enigmatic group of objects, unabsorbed Seyfert 2s may have intrinsically weak broad line regions, obscuration in the line of sight to the BLR but not to the X-ray corona, or so much obscuration that the X-ray continuum is completely suppressed and the observed spectrum is actually scattered into the line of sight from nearby material. NGC 3660 has been shown to have weak broad optical/near infrared lines, no obscuration in the soft X-ray band, and no indication of "changing look"...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1601.02702
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4.0
Jun 29, 2018
06/18
by
Hoi-Fung Yu; Robert D. Preece; Jochen Greiner; P. Narayana Bhat; Elisabetta Bissaldi; Michael S. Briggs; William H. Cleveland; Valerie Connaughton; Adam Goldstein; Andreas von Kienlin; Chryssa Kouveliotou; Bagrat Mailyan; Charles A. Meegan; William S. Paciesas; Arne Rau; Oliver J. Roberts; Péter Veres; Colleen Wilson-Hodge; Bin-Bin Zhang; Hendrik J. van Eerten
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We aim to obtain high-quality time-resolved spectral fits of gamma-ray bursts (GRBs) observed by the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope. We perform time-resolved spectral analysis with high temporal and spectral resolution of the brightest bursts observed by Fermi GBM in its first 4 years of mission. We present the complete catalog containing 1,491 spectra from 81 bursts with high spectral and temporal resolution. Distributions of parameters, statistics...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1601.05206
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6.0
Jun 30, 2018
06/18
by
M. Pietka; R. P. Fender; E. F. Keane
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In this paper we compile the analysis of ~ 200 synchrotron flare events from ~ 90 distinct objects/events for which the distance is well established, and hence the peak luminosity can be accurately estimated. For each event we measure this peak and compare it to the rise and decay timescales, as fit by exponential functions, which allows us in turn to estimate a minimum brightness temperature for all the events. The astrophysical objects from which the flares originate vary from flare stars to...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1411.1067
3
3.0
Jun 30, 2018
06/18
by
J. Takata; Gene C. K. Leung; P. H. T. Tam; A. K. H. Kong; C. Y. Hui; K. S. Cheng
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We study mechanisms of multi-wavelength emissions (X-ray, GeV and TeV gamma-rays) from the gamma-ray binary LS~5039. This paper is composed of two parts. In the first part, we report on results of observational analysis using four year data of \fermi\ Large Area Telescope. Due to the improvement of instrumental response function and increase of the statistics, the observational uncertainties of the spectrum in $\sim$100-300 MeV bands and $>10$GeV bands are significantly improved. The present...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1406.6179
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4.0
Jun 30, 2018
06/18
by
D. Kosenko; G. Ferrand; A. Decourchelle
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We present a library of numerical models of cosmic-ray accelerating supernova remnants (SNRs) evolving through a homogeneous ambient medium. We analyse distributions of the different energy components and diffusive shock acceleration time-scales for the models in various conditions. The library comprises a variety of SNR evolutionary scenarios and is used to map remnants with sufficiently known properties. This mapping constrains the respective ambient medium properties and the acceleration...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1407.1818
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5.0
Jun 30, 2018
06/18
by
Jeremy D. Schnittman
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Supermassive black hole binaries are the strongest gravitational wave sources in the universe. The systems most likely to be observed with pulsar timing arrays (PTAs) will have particularly high masses ($\gtrsim 10^9 M_\odot$), long periods ($T_{\rm orb} \gtrsim 1$ yr), and be in the local universe ($z \lesssim 1$). These features are also the most favorable for bright electromagnetic counterparts, which should be easily observable with existing ground- and space-based telescopes. Wide-field...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1411.3994
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4.0
Jun 30, 2018
06/18
by
O. Porth; S. S. Komissarov
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In stark contrast to their laboratory and terrestrial counterparts, the cosmic jets appear to be very stable. We propose that the reason behind this remarkable property is the loss of causal connectivity across these jets, caused by their rapid expansion in response to fast decline of external pressure with the distance from the "jet engine". In atmospheres with power-law pressure distribution, the total loss of causal connectivity occurs, when the power index k>2 - the steepness...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1408.3318
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3.0
Jun 29, 2018
06/18
by
Mao-Chun Wu; Fu-Guo Xie; Ye-Fei Yuan; Zhao-Ming Gan
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We investigate state transitions in black hole X-ray binaries through different parameters by using two-dimensional axisymmetric hydrodynamical simulation method. For radiative cooling in hot accretion flow, we take into account the bremsstrahlung, synchrotron and synchrotron-self Comptonization self-consistently in the dynamics. Our main result is that the state transitions occur when the accretion rate reaches a critical value $\dot M \sim 3\alpha\ \dot M_{\rm Edd}$, above which cold and...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1604.02283
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3.0
Jun 29, 2018
06/18
by
G. Morlino; M. Lyutikov; M. Vorster
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We investigate the dynamics of bow shock nebulae created by pulsars moving supersonically through a partially ionized interstellar medium. A fraction of interstellar neutral hydrogen atoms penetrating into the tail region of a pulsar wind will undergo photo-ionization due to the UV light emitted by the nebula, with the resulting mass loading dramatically changing the flow dynamics of the light leptonic pulsar wind. Using a quasi 1-D hydrodynamic model of relativistic flow we find that if a...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1604.05143
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3.0
Jun 29, 2018
06/18
by
Damien Turpin; Vincent Heussaff; Jean-Pascal Dezalay; Jean-Luc Atteia; Alain Klotz; Damien Dornic
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Measuring gamma-ray burst (GRB) properties in their rest-frame is crucial to understand the physics at work in gamma-ray bursts. This can only be done for GRBs with known redshift. Since redshifts are usually measured from the optical spectrum of the afterglow, correlations between prompt and afterglow emissions may introduce biases in the distribution of rest-frame properties of the prompt emission. Our analysis is based on a sample of 90 GRBs with good optical follow-up and well measured...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1605.01303
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4.0
Jun 29, 2018
06/18
by
C. W. Ng; J. Takata; K. S. Cheng
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Pulsars are rapidly spinning and highly magnetized neutron stars, with highly stable rotational period and gradual spin-down over a long timescale due to the loss of radiation. Glitches refer to the events that suddenly increase the rotational speed of a pulsar. The exact causes of glitches and the resulting processes are not fully understood. It is generally believed that couplings between the normal matter and the superfluid components, and the starquakes, are the common causes of glitches....
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1605.08968
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6.0
Jun 29, 2018
06/18
by
VERITAS Collaboration; S. Archambault; A. Archer; A. Barnacka; B. Behera; M. Beilicke; W. Benbow; K. Berger; R. Bird; M. Boettcher; J. H. Buckley; V. Bugaev; J. V Cardenzana; M. Cerruti; X. Chen; J. L. Christiansen; L. Ciupik; E. Collins-Hughes; M. P. Connolly; W. Cui; H. J. Dickinson; J. Dumm; J. D. Eisch; M. Errando; A. Falcone; S. Federici; Q. Feng; J. P. Finley; H. Fleischhack; L. Fortson; A. Furniss; G. H. Gillanders; S. Godambe; S. Griffin; S. T. Griffiths; J. Grube; G. Gyuk; N....
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The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours, resulted in the discovery of $\gamma$-ray emission from the blazar, which has a redshift $z$=0.163. 1ES 1440+122 is detected at a statistical significance of 5.5 standard deviations above the background with an integral flux of...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1608.02769
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3.0
Jun 29, 2018
06/18
by
Naomi Tsuji; Yasunobu Uchiyama
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Supernova remnant (SNR) RX J1713.7-3946 is well known for its bright TeV gamma-ray emission with shell-like morphology. To constrain the hydrodynamical evolution, we have performed six times observations of the northwestern (NW) shell with the Chandra X-ray Observatory from 2005 to 2011, and measured the proper motion by using these data and the first epoch observation taken in 2000. The blast-wave shock speed at the NW shell is measured to be $(3900\pm 300) (d/{\rm kpc})\ {\rm km}\ {\rm...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1609.07886
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3.0
Jun 30, 2018
06/18
by
Jason Kaufman; Omer Blaes; Shigenobu Hirose
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Bulk velocities exceed thermal velocities for sufficiently radiation pressure dominated accretion flows. We model the contribution of bulk Comptonization to the soft X-ray excess in AGN. Bulk Comptonization is due to both turbulence and the background shear. We calculate spectra both taking into account and not taking into account bulk velocities using scaled data from radiation magnetohydrodynamic (MHD) shearing box simulations. We characterize our results with temperatures and optical depths...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1701.06704
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4.0
Jun 29, 2018
06/18
by
R. M. T. Connors; S. Markoff; M. A. Nowak; J. Neilsen; C. Ceccobello; P. Crumley; C. S. Froning; E. Gallo; J. E. Nip
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The `fundamental plane of black hole accretion' (FP), a relation between the radio luminosities ($L_R$), X-ray luminosities ($L_X$), and masses ($M_{BH}$) of hard/quiescent state black hole binaries and low-luminosity active galactic nuclei, suggests some aspects of black hole accretion may be scale invariant. However, key questions still exist concerning the relationship between the inflow/outflow behaviour in the `classic' hard state and quiescence, which may impact this scaling. We show that...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1612.00953
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4.0
Jun 29, 2018
06/18
by
A. Sanna; F. Pintore; E. Bozzo; C. Ferrigno; A. Papitto; A. Riggio; T. Di Salvo; R. Iaria; A. D'Aì; E. Egron; L. Burderi
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We report on the spectral and timing properties of the accreting millisecond X-ray pulsar IGR J00291+5934 observed by XMM-Newton and NuSTAR during its 2015 outburst. The source is in a hard state dominated at high energies by a comptonization of soft photons ($\sim0.9$ keV) by an electron population with kT$_e\sim30$ keV, and at lower energies by a blackbody component with kT$\sim0.5$ keV. A moderately broad, neutral Fe emission line and four narrow absorption lines are also found. By...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1612.03865
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5.0
Jun 29, 2018
06/18
by
Akihiro Suzuki; Keiichi Maeda
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eye 5
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The hydrodynamical interaction between freely expanding supernova ejecta and a relativistic wind injected from the central region is studied in analytic and numerical ways. As a result of the collision between the ejecta and the wind, a geometrically thin shell surrounding a hot bubble forms and expands in the ejecta. We use a self-similar solution to describe the early dynamical evolution of the shell and carry out a two-dimensional special relativistic hydrodynamic simulation to follow...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1612.03911
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4.0
Jun 28, 2018
06/18
by
Paolo Maestro
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This paper is based on the rapporteur talk given at the 34$^{th}$ International Cosmic Ray Conference (ICRC), on August 6$^{th}$, 2015. The purpose of the talk and paper is to provide a summary of the most recent results from balloon-borne and space-based experiments presented at the conference, and give an overview of the future missions and developments foreseen in this field.
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1510.07683
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5.0
Jun 29, 2018
06/18
by
J. M. Miller; J. Raymond; A. C. Fabian; E. Gallo; J. Kaastra; T. Kallman; A. L. King; D. Proga; C. S. Reynolds; A. Zoghbi
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We report on a 120 ks Chandra/HETG spectrum of the black hole GRS 1915+105. The observation was made during an extended and bright soft state in June, 2015. An extremely rich disk wind absorption spectrum is detected, similar to that observed at lower sensitivity in 2007. The very high resolution of the third-order spectrum reveals four components to the disk wind in the Fe K band alone; the fastest has a blue-shift of v = 0.03c. Broadened re-emission from the wind is also detected in the...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1603.01474
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10.0
Jun 29, 2018
06/18
by
Roberta Del Vecchio; Maria Giovanna Dainotti; Michał Ostrowski
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eye 10
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In this work we study the distribution of temporal power-law decay indices, $\alpha$, in the Gamma Ray Burst (GRB) afterglow phase, fitted for $176$ GRBs (139 long GRBs, 12 short GRBs {\it with extended emission} and 25 X-Ray Flashes (XRFs)) with known redshifts. These indices are compared with the temporal decay index, $\alpha_W$, derived with the light curve fitting using the \cite{willingale07} model. This model fitting yields similar distributions of $\alpha_W$ to the fitted $\alpha$, but...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1603.04183
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4.0
Jun 29, 2018
06/18
by
V. Karamanavis; L. Fuhrmann; E. Angelakis; I. Nestoras; I. Myserlis; T. P. Krichbaum; J. A. Zensus; H. Ungerechts; A. Sievers; M. A. Gurwell
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Context. The origin of blazar variability, seen from radio up to gamma rays, is still a heavily debated matter and broadband flares offer a unique testbed towards a better understanding of these extreme objects. Such an energetic outburst was detected by Fermi/LAT in 2008 from the blazar PKS 1502+106. The outburst was observed from gamma rays down to radio frequencies. Aims. Through the delay between flare maxima at different radio frequencies, we study the frequency-dependent position of the...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1603.04220
