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Sep 18, 2013
09/13
by
Fabian Walter
texts
eye 52
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High resolution HI observations of nearby dwarf galaxies (most of which are situated in the M 81 group at a distance of about 3.2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M 31 and M 33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's...
Source: http://arxiv.org/abs/astro-ph/9903485v1
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Sep 23, 2013
09/13
by
Fabian Walter
texts
eye 45
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Although dust emission at cosmological distances has only been detected a little more than a decade ago, remarkable progress has been achieved since then in characterizing the far-infrared emission of high-redshift systems. The mere fact that dust can be detected in galaxies at high redshift is remarkable for two reasons: (a) even at very early cosmic epochs (all the way to the first Gyr of the universe), dust production was apparently very effective, (b) due to the inverse K-correction (`the...
Source: http://arxiv.org/abs/0904.0152v1
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4.0
Jan 6, 2021
01/21
by
Fabian Walter (MouZ304)
data
eye 4
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It's design for Kania (Lidl) Glass Spices and others I oriented to the design of https://www.thingiverse.com/thing:4505323 It is to see on the bottom in the Picture Do you like my Things?
Topics: Kania, stl, Lidl, holder, 3D Printer Parts, thingiverse, Spice
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3.0
Jun 11, 2021
06/21
by
Fabian Walter (MouZ304)
data
eye 3
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It is design for a Hexagon nuts, low shaped (ISO 4035). If the inside diameter doesn't fit, use an 8 mm drill. Use it with a headless screw with hexagon socket m4x10 (DIN 913)
Topics: Locking Ring, 8mm, 3D Printer Parts, Lock Ring, thingiverse, Smooth Rod, stl
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3.0
Apr 2, 2021
04/21
by
Fabian Walter (MCFab27)
data
eye 3
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Customized version of https://www.thingiverse.com/thing:2771040 Created with Customizer! https://www.thingiverse.com/apps/customizer/run?thing_id=2771040
Topics: Camera, customized, stl, thingiverse
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3.0
Apr 2, 2021
04/21
by
Fabian Walter (MCFab27)
data
eye 3
favorite 0
comment 0
Customized version of https://www.thingiverse.com/thing:2771040 Created with Customizer! https://www.thingiverse.com/apps/customizer/run?thing_id=2771040
Topics: Camera, customized, stl, thingiverse
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3.0
Sep 14, 2021
09/21
by
Fabian Walter (MouZ304)
data
eye 3
favorite 0
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Spice Jar (like Ostmann) I oriented to the design of https://www.thingiverse.com/thing:4122253 Optimal use in my Spice Holder https://www.thingiverse.com/thing:4652388 Do you like my Things?
Topics: stl, thingiverse, Ostmann, Spice, 3D Printer Parts, Jar
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Sep 18, 2013
09/13
by
Andreas Heithausen; Fabian Walter
texts
eye 52
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Using the IRAM 30m radio telescope we have mapped the tidal arm feature south-east of NGC3077 where we recently detected molecular gas in the CO (J=1-0) and (2-1) transitions. We find that the molecular gas is much more extended than previously thought (several kpc). The CO emission can be separated into at least 3 distinct complexes with equivalent radii between 250pc and 700pc and all well confined over a narrow range in velocity. For one complex we have also obtained a CO (3-2) spectrum...
Source: http://arxiv.org/abs/astro-ph/0006374v1
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Sep 21, 2013
09/13
by
Chris Carilli; Fabian Walter
texts
eye 48
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Over the last decade, observations of the cool interstellar medium in distant galaxies via molecular and atomic fine structure line emission has gone from a curious look into a few extreme, rare objects, to a mainstream tool to study galaxy formation, out to the highest redshifts. Molecular gas has now been observed in close to 200 galaxies at z>1, including numerous AGN host-galaxies out to z~7, highly starforming sub-millimeter galaxies (median redshift z~2.5), and increasing samples of...
Source: http://arxiv.org/abs/1301.0371v2
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46
Sep 23, 2013
09/13
by
Fabian Walter; Andreas Heithausen
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eye 46
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We present the discovery of a giant molecular complex (r=350 pc, M_ vir=10^7 M_sun) in the tidal arms south-east of NGC 3077, a member of the M 81 triplet. The complex is clearly detected in the 12CO (J=1-0) transition at five independent positions. The position relative to NGC 3077, the systemic velocity (v_hel=14km/s) and the cloud averaged line width (15km/s) indicate that the object is not related to Galactic cirrus but is extragalactic. The tidal HI arm where the molecular complex is...
Source: http://arxiv.org/abs/astro-ph/9904423v1
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Sep 23, 2013
09/13
by
Fabian Walter; Elias Brinks
texts
eye 60
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We present HI synthesis observations of the nearby dwarf galaxy IC 2574 (a member of the M81 group of galaxies) made with the NRAO Very Large Array at high spatial and velocity resolution (95 pc x 2.6 km/s). The VLA HI observations show a stunning amount of detail in the form of 48 mostly expanding HI shells and holes in its neutral interstellar medium. These features range in size from about 100 (a limit set by the size of the beam) to about 1000 pc dominating the appearance of the HI surface...
Source: http://arxiv.org/abs/astro-ph/9904002v1
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48
Sep 18, 2013
09/13
by
Fabian Walter; Chris Carilli
texts
eye 48
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Detecting and studying objects at the highest redshifts, out to the end of Cosmic Reionization at z>7, is clearly a key science goal of ALMA. ALMA will in principle be able to detect objects in this redshift range both from high-J (J>7) CO transitions and emission from ionized carbon, [CII], which is one of the main cooling lines of the ISM. ALMA will even be able to resolve this emission for individual targets, which will be one of the few ways to determine dynamical masses for systems...
Source: http://arxiv.org/abs/0704.1858v1
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Sep 18, 2013
09/13
by
Fabian Walter; Andreas Heithausen
texts
eye 47
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Using the IRAM 30m radio telescope we have mapped the tidal arm feature south-east of NGC 3077 where we recently detected molecular gas in the CO (1-0) and (2-1) transitions. We find that the molecular gas is much more extended than previously thought (several kpc). The CO emission can be separated into at least 3 distinct complexes with equivalent radii between 250pc and 700pc - the newly detected complexes therefore range among the largest molecular complexes in the local universe. Mass...
Source: http://arxiv.org/abs/astro-ph/0008347v1
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Sep 17, 2013
09/13
by
Susan G. Stewart; Fabian Walter
texts
eye 44
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A multi-band analysis of the region containing the supergiant HI shell in the nearby dwarf irregular galaxy IC2574 presents evidence of a causal relationship between a central star cluster, the surrounding expanding HI shell, and secondary star formation sites on the rim of the HI shell. Comparisons of the far-UV (FUV, 1521 A), optical broad-band, H-alpha, X-ray, and HI morphologies suggest that the region is in an auspicious moment of star formation triggered by the central stellar cluster....
Source: http://arxiv.org/abs/astro-ph/0007077v1
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39
Sep 21, 2013
09/13
by
Juergen Kerp; Fabian Walter; Elias Brinks
texts
eye 39
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We present a study of the irregular dwarf galaxy Holmberg II based on ROSAT PSPC observations (total exposure time: 22 ksec). Holmberg II is a nearby (3.2 Mpc), well-studied dwarf irregular galaxy. It is famous for its interstellar medium which is dominated by expanding structures such as HI holes and shells. We search for X-ray emission from point sources as well as for diffuse emission, down to the detection limit of the ROSAT data. Using X-ray hardness ratio diagrams we differentiate between...
Source: http://arxiv.org/abs/astro-ph/0203434v1
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Oct 25, 2014
10/14
by
Sultana, Nargis; Fabian, Walter M F
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eye 52
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This article is from Beilstein Journal of Organic Chemistry , volume 9 . Abstract The reaction of cyclobutane-1,2-dione with hydroxide was studied by a variety of ab initio (MP2, SCS-MP2, CCSD(T), CEPA/1) and density functional (M06-2X) methods. Three possible reaction paths of the initially formed tetrahedral adduct leading to either 1-hydroxycyclopropane-1-carboxylate (benzilic acid type rearrangement, path A), α-oxobutanoate (path B) or γ-oxobutanoate (path C) were considered. Although the...
Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3628910
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52
Sep 22, 2013
09/13
by
Juergen Ott; Fabian Walter; Elias Brinks
texts
eye 52
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(abridged) We present an analysis of Chandra X-ray observations of a sample of eight dwarf starburst galaxies (I Zw 18, VII Zw 403, NGC 1569, NGC 3077, NGC 4214, NGC 4449, NGC 5253, and He 2-10). Extended, diffuse X-ray emission is detected in all but two of the objects. Unresolved sources were found within all dwarf galaxies (total: 55 sources). These point sources are well fit by power law, thermal plasma, or black body models. Ten of the point sources exceed an X-ray luminosity of 10^39 erg...
Source: http://arxiv.org/abs/astro-ph/0501525v1
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Sep 22, 2013
09/13
by
Fabian Walter; Chris Carilli; Emanuele Daddi
texts
eye 53
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In order to understand galaxy evolution through cosmic times it is critical to derive the properties of the molecular gas content of galaxies, i.e. the material out of which stars ultimately form. The last decade has seen rapid progress in this area, with the detection of massive molecular gas reservoirs at high redshifts in submillimeter-selected galaxies and quasars. In the latter case, molecular gas reservoirs have been quantified out to redshifts z>6, i.e. towards the end of cosmic...
Source: http://arxiv.org/abs/1101.4022v1
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Sep 18, 2013
09/13
by
Fabian Walter; Axel Weiss; Nick Scoville
texts
eye 66
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We present a high-resolution (3.6'', 70pc) CO(1-0) mosaic of the molecular gas in M 82 covering an area of 2.5' x 3.5' (2.8kpc x 3.9kpc) obtained with the OVRO millimeter interferometer. The observations reveal the presence of huge amounts of molecular gas (> 70% of the total molecular mass, M_tot=1.3 x 10^9 M_sun) outside the central 1 kpc disk. Molecular streamers are detected in and below M82's disk out to distances from the center of 1.7 kpc. Some of these streamers are well correlated...
Source: http://arxiv.org/abs/astro-ph/0210602v1
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39
Sep 18, 2013
09/13
by
Andreas Heithausen; Christoph Boettner; Fabian Walter
texts
eye 39
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We present a comparative study of several molecular lines and of the dust contiunuum at 1.2mm in a pre-stellar core that is embedded in the Galactic cirrus cloud MCLD123.5+24.9. Previous studies found that the core is gravitationally stable and shows signs of inward motion. Using the Owens Valley (OVRO) and Plateau de Bure (PdB) interferometers we obtained high-angular resolution maps of the core in the carbon monosulfide CS 2-1 and the cyanoacetylene HC3N 10-9 transitions. Together with CS...
Source: http://arxiv.org/abs/0806.4690v1
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43
Sep 22, 2013
09/13
by
Michael Kappes; Juergen Kerp; Fabian Walter
texts
eye 43
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We present an XMM-Newton observation of the nearby dwarf galaxy IC 2574. This galaxy is part of our ensemble observed within a multi-frequency campaign to study the physical conditions of the interstellar medium in dwarf galaxies in general. Here, we focus on the diffuse soft (0.2 - 0.5 keV) X-ray emission associated with IC 2574. Since this emission is expected to be quite faint we have to reach the true X-ray background intensity level. For this aim, we have to account for unrelated diffuse...
Source: http://arxiv.org/abs/astro-ph/0307498v1
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Sep 22, 2013
09/13
by
Juergen Ott; Fabian Walter; Elias Brinks
texts
eye 58
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(abridged) We present a comprehensive comparison of the X-ray properties of a sample of eight dwarf starburst galaxies observed with Chandra (I Zw 18, VII Zw 403, NGC 1569, NGC 3077, NGC 4214, NGC 4449, NGC 5253, He 2-10). In Paper I we presented in detail the data reduction and analysis of the individual galaxies. For the unresolved X-ray sources we find the following: point sources are in general located close to bright HII regions, rims of superbubbles, or young stellar clusters. The number...
Source: http://arxiv.org/abs/astro-ph/0501528v1
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105
Sep 17, 2013
09/13
by
Juergen Ott; Crystal L. Martin; Fabian Walter
texts
eye 105
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Deep Chandra observations (53 ks, ACIS-S3) of NGC 3077, a starburst dwarf galaxy in the M 81 triplet, resolve the X-ray emission from several supershells. The emission is brightest in the cavities defined by expanding shells detected previously in H alpha emission (Martin 1998). Thermal emission models fitted to the data imply temperatures ranging from ~1.3 to 4.9 x 10^(6) K and indicate that the strongest absorption is coincident with the densest clouds traced by CO emission. The fitted...
Source: http://arxiv.org/abs/astro-ph/0305148v1
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40
Sep 21, 2013
09/13
by
Elias Brinks; Pierre-Alain Duc; Fabian Walter
texts
eye 40
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We present high resolution interferometric observations of the cool atomic and cold molecular ISM of the TDG candidate Arp 245N, an object resembling a dwarf galaxy in the northern tidal tail of the interacting system NGC 2992/3. We observed the HI line with the NRAO VLA and the CO(1-->0) transition with the OVRO millimeter interferometer at 5''-6'' angular resolution (750 pc linear resolution). These datacubes offer the required spatial and velocity resolution to determine whether the mass...
Source: http://arxiv.org/abs/astro-ph/0402274v1
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40
Sep 19, 2013
09/13
by
Elias Brinks; Fabian Walter; Evan D. Skillman
texts
eye 40
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Recent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~1e5 Msol) HI clouds with no obvious optical counterparts. We have searched 10 fields in the M81 group totalling 2.2 square degree, both targeting known dwarf spheroidal galaxies and blank fields around the central triplet. Our observations show that the new population of low-mass HI clouds appears to be confined to a region toward the South-East of...
Source: http://arxiv.org/abs/0708.2836v1
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48
Sep 18, 2013
09/13
by
David Weldrake; Erwin de Blok; Fabian Walter
texts
eye 48
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We present high resolution rotation curves of the local group dwarf irregular galaxy NGC 6822 obtained with the Australia Telescope Compact Array. Our best curves have an angular resolution of 8'' or 20 pc and contain some 250 independent points. The stellar and gas components of NGC 6822 cannot explain the shape of the curve, except for the very inner regions, and NGC 6822 is consequently very dark matter dominated. There is no evidence for the presence of a steep density cusp down to scales...
Source: http://arxiv.org/abs/astro-ph/0210568v1
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51
Sep 18, 2013
09/13
by
Christopher L. Taylor; Fabian Walter; Min S. Yun
texts
eye 51
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We present the first fully sampled map of 12CO (1-0) emission from M82 covering the entire galaxy. Our map contains a 12 x 15 kpc^2 area. We find that extraplanar CO emission, previously reported at short distances above the galactic plane, extends to heights of up to 6 kpc above the disk. Some of this emission is associated with tidal arms seen in HI, implying either that M82 contained substantial amounts of molecular gas in the outer disk, or that molecular gas formed after the tidal...
Source: http://arxiv.org/abs/astro-ph/0110283v1
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70
Sep 23, 2013
09/13
by
Axel Weiss; Fabian Walter; Nikolaus Neininger; Uli Klein
texts
eye 70
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We present evidence for an expanding superbubble in M82 (diameter: ~130 pc, expansion velocity: ~45 km/s, mass: ~8*10^6 SM). It is seen in the 12CO(J=1-0), 12CO(J=2-1), 13CO(J=1-0) and C18O(J=1-0) lines. The superbubble is centred around the most powerful supernova remnant in M82, 41.9+58. The CO observations show that the molecular superbubble already broke out of the disk. This scenario is supported by ROSAT HRI observations which suggest that hot coronal gas originating from inside the shell...
Source: http://arxiv.org/abs/astro-ph/9904081v1
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38
Sep 18, 2013
09/13
by
Juergen Ott; Axel Weiss; Christian Henkel; Fabian Walter
texts
eye 38
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[abridged] We present interferometric maps of ammonia (NH3) of the nearby starburst galaxy NGC 253 [star formation rate: ~2.8 Mo yr^(-1)]. The observations have been taken with the Australia Telescope Compact Array and include the para-NH3 (1,1), (2,2), and the ortho-NH3 (3,3) and (6,6) inversion lines. Six major complexes of dense ammonia are identified, three of them on either side of the starburst center, out to projected galactocentric radii of \~250 pc. [...] The application of radiative...
Source: http://arxiv.org/abs/astro-ph/0505143v1
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39
Sep 19, 2013
09/13
by
Dominik A. Riechers; Axel Weiss; Fabian Walter; Jeff Wagg
texts
eye 39
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We report the detection of surprisingly strong HCN, HNC, and HCO+(J=6-5) emission in the host galaxy of the z=3.91 quasar APM08279+5255 through observations with CARMA. HCN, HNC, and HCO+ are typically used as star formation indicators, tracing dense molecular hydrogen gas [n(H2) > 10^5,cm^-3] within star-forming molecular clouds. However, the strength of their respective line emission in the J=6-5 transitions in APM08279+5255 is extremely high, suggesting that they are excited by another...
Source: http://arxiv.org/abs/1010.2485v1
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66
Sep 19, 2013
09/13
by
Kelly Foyle; Hans-Walter Rix; Fabian Walter; Adam Leroy
texts
eye 66
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We investigate the relationship between spiral arms and star formation in the grand-design spirals NGC 5194 and NGC 628 and in the flocculent spiral NGC 6946. Filtered maps of near-IR (3.6 micron) emission allow us to identify "arm regions" that should correspond to regions of stellar mass density enhancements. The two grand-design spirals show a clear two-armed structure, while NGC 6946 is more complex. We examine these arm and interarm regions, looking at maps that trace recent star...
Source: http://arxiv.org/abs/1010.0678v1
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52
Sep 23, 2013
09/13
by
Dominik A. Riechers; Fabian Walter; Christopher L. Carilli; Frank Bertoldi
texts
eye 52
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We report a sensitive search for the HCN(J=2-1) emission line towards SDSS J1148+5251 at z=6.42 with the VLA. HCN emission is a star formation indicator, tracing dense molecular hydrogen gas (n(H2) >= 10^4 cm^-3) within star-forming molecular clouds. No emission was detected in the deep interferometer maps of J1148+5251. We derive a limit for the HCN line luminosity of L'(HCN) < 3.3 x 10^9 K km/s pc^2, corresponding to a HCN/CO luminosity ratio of L'(HCN)/L'(CO) < 0.13. This limit is...
Source: http://arxiv.org/abs/0710.4525v1
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7.0
Jun 30, 2018
06/18
by
Lindley Lentati; Chris Carilli; Paul Alexander; Fabian Walter; Roberto Decarli
texts
eye 7
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A new Bayesian method for performing an image domain search for line-emitting galaxies is presented. The method uses both spatial and spectral information to robustly determine the source properties, employing either simple Gaussian, or other physically motivated models whilst using the evidence to determine the probability that the source is real. In this paper, we describe the method, and its application to both a simulated data set, and a blind survey for cold molecular gas using...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1408.3585
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53
Sep 19, 2013
09/13
by
Jonathan C. Tan; Henrik Beuther; Fabian Walter; Eric G. Blackman
texts
eye 53
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Supermassive black holes in giant elliptical galaxies are remarkably faint given their expected accretion rates. This motivates models of radiatively inefficient accretion, due to either ion-electron thermal decoupling, generation of outflows that inhibit accretion, or settling of gas to a gravitationally unstable disk that forms stars in preference to feeding the black hole. The latter model predicts the presence of cold molecular gas in a thin disk around the black hole. Here we report...
Source: http://arxiv.org/abs/astro-ph/0610488v4
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Sep 23, 2013
09/13
by
Fabian Walter; Jürgen Kerp; Neb Duric; Elias Brinks; Uli Klein
texts
eye 52
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We present a multi--wavelength study of a supergiant shell within the violent interstellar medium of the nearby dwarf galaxy IC 2574, a member of the M81 group of galaxies. Neutral hydrogen (HI) observations obtained with the Very Large Array (VLA) reveal a prominent expanding supergiant HI shell which is thought to be produced by the combined effects of stellar winds and supernova explosions. It measures roughly 1000 x 500 pc in size and is expanding at about 25 km/s. The HI data suggest an...
Source: http://arxiv.org/abs/astro-ph/9806112v1
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39
Sep 19, 2013
09/13
by
Dominik A. Riechers; Christopher L. Carilli; Fabian Walter; Emmanuel Momjian
texts
eye 39
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We report the detection of CO(1-0) emission toward the lensed L*_UV Lyman-break galaxies (LBGs) MS1512-cB58 (z=2.73) and the Cosmic Eye (z=3.07), using the Expanded Very Large Array. The strength of the CO line emission reveals molecular gas reservoirs with masses of (4.6+/-1.1) x 10^8 (mu_L/32)^-1 (alpha_CO/0.8) Msun and (9.3+/-1.6) x 10^8 (mu_L/28)^-1 (alpha_CO/0.8) Msun, respectively. These observations suggest by ~30%-40% larger gas reservoirs than estimated previously based on CO(3-2)...
Source: http://arxiv.org/abs/1010.4299v1
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51
Sep 18, 2013
09/13
by
Adam Leroy; John Cannon; Fabian Walter; Alberto Bolatto; Axel Weiss
texts
eye 51
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We present sensitive molecular line observations of the metal-poor blue compact dwarf I Zw 18 obtained with the IRAM Plateau de Bure interferometer. These data constrain the CO J=1-0 luminosity within our 300 pc (FWHM) beam to be L_CO < 1 \times 10^5 K km s^-1 pc^2 (I_CO < 1 K km s^-1), an order of magnitude lower than previous limits. Although I Zw 18 is starbursting, it has a CO luminosity similar to or less than nearby low-mass irregulars (e.g. NGC 1569, the SMC, and NGC 6822). There...
Source: http://arxiv.org/abs/0704.0862v1
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41
Sep 22, 2013
09/13
by
Fabian Walter; Axel Weiss; Dennis Downes; Roberto Decarli; Christian Henkel
texts
eye 41
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We present a survey of atomic carbon (CI) emission in high-redshift (z>2) submillimeter galaxies (SMGs) and quasar host galaxies (QSOs). Sensitive observations of the CI(3P_1->3P_0) and CI(3P_2->3P_1) lines have been obtained at the IRAM Plateau de Bure interferometer and the IRAM 30m telescope. A total of 16 CI lines have been targeted in 10 sources, leading to a total of 10 detected lines --- this doubles the number of CI observations at high redshift to date. We include previously...
Source: http://arxiv.org/abs/1101.4027v1
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48
Sep 23, 2013
09/13
by
Kelly Foyle; Hans-Walter Rix; Clare Dobbs; Adam Leroy; Fabian Walter
texts
eye 48
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We test whether the spiral patterns apparent in many large disk galaxies should be thought of as dynamical features that are stationary in a co-rotating frame for > t_{dyn}, as implied by the density wave approach for explaining spiral arms. If such spiral arms have enhanced star formation (SF), observational tracers for different stages of the SF sequence should show a spatial ordering, from up-stream to downstream in the corotating frame: dense HI, CO, tracing molecular hydrogen gas, 24...
Source: http://arxiv.org/abs/1105.5141v1
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64
Sep 18, 2013
09/13
by
Dominik A. Riechers; Fabian Walter; Christopher L. Carilli; Geraint F. Lewis
texts
eye 64
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We have mapped the molecular gas content in the host galaxy of the strongly lensed high redshift quasar APM 08279+5255 (z=3.911) with the Very Large Array at 0.3" resolution. The CO(J=1-0) emission is clearly resolved in our maps. The CO(J=1-0) line luminosity derived from these maps is in good agreement with a previous single-dish measurement. In contrast to previous interferometer-based studies, we find that the full molecular gas reservoir is situated in two compact peaks separated by
Source: http://arxiv.org/abs/0809.0754v1
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Sep 19, 2013
09/13
by
Andreas Schruba; Adam K. Leroy; Fabian Walter; Karin Sandstrom; Erik Rosolowsky
texts
eye 38
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We study the Local Group spiral galaxy M33 to investigate how the observed scaling between the (kpc-averaged) surface density of molecular gas (\Sigma_H2) and recent star formation rate (\Sigma_SFR) relates to individual star-forming regions. To do this, we measure the ratio of CO emission to extinction-corrected Halpha emission in apertures of varying sizes centered both on peaks of CO and Halpha emission. We parameterize this ratio as a molecular gas (H_2) depletion time (\tau_dep). On large...
Source: http://arxiv.org/abs/1009.1651v1
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56
Sep 18, 2013
09/13
by
John M. Cannon; Fabian Walter; Evan D. Skillman; Liese van Zee
texts
eye 56
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We present the first resolved study of the radio continuum properties of I Zw 18, the dwarf galaxy with the lowest known nebular metal abundance in the local universe. New Very Large Array radio continuum images at 20 and 3.6 cm are compared to various Hubble Space Telescope images, and we find a striking morphological similarity between high-resolution H alpha and short wavelength radio continuum emission, especially in the H alpha shell in the northwest region. We separate thermal and...
Source: http://arxiv.org/abs/astro-ph/0502059v1
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66
Sep 20, 2013
09/13
by
R. Ianjamasimanana; W. J. G. de Blok; Fabian Walter; George H. Heald
texts
eye 66
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We analyze the shapes of the HI velocity profiles of The HI Nearby Galaxy Survey (THINGS) to study the phase structure of the neutral interstellar medium (ISM) and its relation to global galaxy properties. We use a method analogous to the stacking method sometimes used in high redshift HI observations to construct high signal-to-noise (S/N) profiles. We call these high S/N profiles super profiles. We analyze and discuss possible systematics that may change the observed shapes of the super...
Source: http://arxiv.org/abs/1207.5041v1
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89
Jul 24, 2013
07/13
by
Alberto D. Bolatto; Adam K. Leroy; Erik Rosolowsky; Fabian Walter; Leo Blitz
texts
eye 89
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We use high spatial resolution observations of CO to systematically measure the resolved size-line width, luminosity-line width, luminosity-size, and the mass-luminosity relations of Giant Molecular Clouds (GMCs) in a variety of extragalactic systems. Although the data are heterogeneous we analyze them in a consistent manner to remove the biases introduced by limited sensitivity and resolution, thus obtaining reliable sizes, velocity dispersions, and luminosities. We compare the results...
Source: http://arxiv.org/abs/0807.0009v2
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Sep 23, 2013
09/13
by
Alberto D. Bolatto; Adam K. Leroy; Erik Rosolowsky; Fabian Walter; Leo Blitz
texts
eye 46
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Giant molecular clouds (GMCs) are the major reservoirs of molecular gas in galaxies, and the starting point for star formation. As such, their properties play a key role in setting the initial conditions for the formation of stars. We present a comprehensive combined inteferometric/single-dish study of the resolved GMC properties in a number of extragalactic systems, including both normal and dwarf galaxies. We find that the extragalactic GMC properties measured across a wide range of...
Source: http://arxiv.org/abs/0810.2726v1
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99
Sep 23, 2013
09/13
by
Dominik A. Riechers; Jacqueline Hodge; Fabian Walter; Christopher L. Carilli; Frank Bertoldi
texts
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We report the detection of spatially resolved CO(1-0) emission in the z~3.4 submillimeter galaxies (SMGs) SMM J09431+4700 and SMM J13120+4242, using the Expanded Very Large Array (EVLA). SMM J09431+4700 is resolved into the two previously reported millimeter sources H6 and H7, separated by ~30kpc in projection. We derive CO(1-0) line luminosities of L'(CO 1-0) = (2.49+/-0.86) and (5.82+/-1.22) x 10^10 K km/s pc^2 for H6 and H7, and L'(CO 1-0) = (23.4+/-4.1) x 10^10 K km/s pc^2 for SMM...
Source: http://arxiv.org/abs/1105.4177v1
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38
Sep 21, 2013
09/13
by
Dominik A. Riechers; Fabian Walter; Christopher L. Carilli; Frank Bertoldi; Emmanuel Momjian
texts
eye 38
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We present high-resolution Very Large Array imaging of the molecular gas in the host galaxy of the high redshift quasar BRI 1335-0417 (z=4.41). Our CO(2-1) observations have a linear resolution of 0.15" (1.0 kpc) and resolve the molecular gas emission both spatially and in velocity. The molecular gas in BRI 1335-0417 is extended on scales of 5 kpc, and shows a complex structure. At least three distinct components encompassing about two thirds of the total molecular mass of 9.2 x 10^10...
Source: http://arxiv.org/abs/0808.3774v1
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58
Sep 21, 2013
09/13
by
Alberto D. Bolatto; Adam Leroy; Josh D. Simon; Leo Blitz; Fabian Walter
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We present results from an extensive survey of molecular gas in nearby dwarf galaxies. This survey consists of a single-dish search for CO emission at the UASO Kitt Peak 12m telescope and interferometric follow-up using the Berkeley-Illinois-Maryland Array. We have detected 41 new sources, approximately doubling the number of detections of such objects in the literature. In this paper we discuss two results from the survey that lead us to agree with recent suggestions that, above a metallicity...
Source: http://arxiv.org/abs/astro-ph/0311258v1
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107
Jul 20, 2013
07/13
by
Rahul Kannan; Andrea V. Macciò; Anna Pasquali; Benjamin P. Moster; Fabian Walter
texts
eye 107
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We investigate the idea that the interaction of Dark Matter (DM) sub-halos with the gaseous disk of galaxies can be the origin for the observed holes and shells found in their neutral hydrogen (HI) distributions. We use high resolution hydrodynamic simulations to show that pure DM sub-halos impacting a galactic disk are not able to produce holes; on the contrary, they result in high density regions in the disk. However, sub-halos containing a small amount of gas (a few percent of the total DM...
Source: http://arxiv.org/abs/1107.2401v2
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47
Sep 18, 2013
09/13
by
Dominik A. Riechers; Axel Weiss; Fabian Walter; Christopher L. Carilli; Kirsten K. Knudsen
texts
eye 47
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We present a search for 183 GHz H_2O(3_13-2_20) emission in the infrared-luminous quasar MG 0751+2716 with the NRAO Very Large Array (VLA). At z=3.200+/-0.001, this water emission feature is redshifted to 43.6 GHz. As opposed to the faint rotational transitions of HCN (the standard high-density tracer at high-z), H_2O(3_13-2_20) is observed with high maser amplification factors in Galactic star-forming regions. It therefore holds the potential to trace high-density star-forming regions in the...
Source: http://arxiv.org/abs/astro-ph/0605499v1
