48
48
Sep 18, 2013
09/13
by
B. P. Miller; C. A. Welling; W. N. Brandt; R. R. Gibson
texts
eye 48
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We present preliminary results from an investigation into broad absorption line (BAL) variability within a sample of 41 radio-loud quasars (RLQs). Using 28 new Hobby-Eberly Telescope (HET) spectra along with earlier Sloan Digital Sky Survey (SDSS) or other archival data, we generate a total set of 50 pairs of BAL equivalent width measurements. Absorption variability in BAL RLQs typically consists of modest changes in the depth of trough segments, and variability is more common on longer...
Source: http://arxiv.org/abs/1201.2676v1
40
40
Sep 19, 2013
09/13
by
W. N. Brandt; G. Chartas; S. C. Gallagher; R. R. Gibson; B. P. Miller
texts
eye 40
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We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback. Topics covered include (1) Relations between X-ray and UV absorption in Broad Absorption Line (BAL) and mini-BAL quasars; (2) X-ray absorption in radio-loud BAL quasars; and (3) Evidence for relativistic iron K BALs in the X-ray spectra of a few bright quasars. We also mention some key...
Source: http://arxiv.org/abs/0909.0958v1
3
3.0
Jun 30, 2018
06/18
by
C. A. Welling; B. P. Miller; W. N. Brandt; D. M. Capellupo; R. R. Gibson
texts
eye 3
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We investigate C IV broad absorption line (BAL) variability within a sample of 46 radio-loud quasars (RLQs), selected from SDSS/FIRST data to include both core-dominated (39) and lobe-dominated (7) objects. The sample consists primarily of high-ionization BAL quasars, and a substantial fraction have large BAL velocities or equivalent widths; their radio luminosities and radio-loudness values span ~2.5 orders of magnitude. We have obtained 34 new Hobby-Eberly Telescope (HET) spectra of 28 BAL...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1403.0958
40
40
Sep 19, 2013
09/13
by
B. P. Miller; W. N. Brandt; D. P. Schneider; R. R. Gibson; A. T. Steffen; Jianfeng Wu
texts
eye 40
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We present the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). We combine large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs and 603 RLQs. This sample is constructed independently of X-ray properties but has a high X-ray detection rate (85%); it provides broad and dense...
Source: http://arxiv.org/abs/1010.4804v1
55
55
Sep 20, 2013
09/13
by
A. J. Young; J. C. Lee; A. C. Fabian; C. S. Reynolds; R. R. Gibson; C. R. Canizares
texts
eye 55
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We present a high resolution X-ray spectrum of the iron K bandpass in MCG-6-30-15 based on a 522 ksec observation with Chandra's High Energy Transmission Grating Spectrometer. The Chandra spectrum is consistent with the presence of a relativistically broadened, highly redshifted iron K alpha emission line with a similar profile to previous observations. A number of narrow features are detected above 2 keV, including a narrow Fe K alpha emission line and narrow absorption lines from H- and...
Source: http://arxiv.org/abs/astro-ph/0506082v1
60
60
Sep 19, 2013
09/13
by
Patrick B. Hall; Konstantin Anosov; R. L. White; W. N. Brandt; M. D. Gregg; R. R. Gibson; R. H. Becker; D. P. Schneider
texts
eye 60
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We have observed a dramatic change in the spectrum of the formerly heavily absorbed `overlapping-trough' iron low-ionization broad absorption line (FeLoBAL) quasar FBQS J1408+3054. Over a time span of between 0.6 to 5 rest-frame years, the Mg II trough outflowing at 12,000 km/s decreased in equivalent width by a factor of two and the Fe II troughs at the same velocity disappeared. The most likely explanation for the variability is that a structure in the BAL outflow moved out of our line of...
Source: http://arxiv.org/abs/1010.3728v2
4
4.0
Jun 30, 2018
06/18
by
A. E. Scott; W. N. Brandt; E. Behar; D. M. Crenshaw; J. R. Gabel; R. R. Gibson; S. Kaspi; S. B. Kraemer; T. J. Turner
texts
eye 4
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We present the results of recent Chandra High-Energy Transmission Grating Spectrometer and Hubble Space Telescope Cosmic Origins Spectrograph observations of the nearby Seyfert 1 galaxy NGC 3783 which shows a strong, non-varying X-ray warm absorber and physically related and kinematically varying UV absorption. We compare our new observations to high-resolution, high signal-to-noise archival data from 2001, allowing a unique investigation into the long-term variations of the absorption over a...
Topics: High Energy Astrophysical Phenomena, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1410.4569
14
14
Jun 27, 2018
06/18
by
B. Luo; W. N. Brandt; P. B. Hall; Jianfeng Wu; S. F. Anderson; G. P. Garmire; R. R. Gibson; R. M. Plotkin; G. T. Richards; D. P. Schneider; O. Shemmer; Yue Shen
texts
eye 14
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We present an X-ray and multiwavelength study of 33 weak emission-line quasars (WLQs) and 18 quasars that are analogs of the extreme WLQ, PHL 1811, at z ~ 0.5-2.9. New Chandra 1.5-9.5 ks exploratory observations were obtained for 32 objects while the others have archival X-ray observations. Significant fractions of these luminous type 1 quasars are distinctly X-ray weak compared to typical quasars, including 16 (48%) of the WLQs and 17 (94%) of the PHL 1811 analogs with average X-ray weakness...
Topics: Astrophysics of Galaxies, Astrophysics, High Energy Astrophysical Phenomena, Cosmology and...
Source: http://arxiv.org/abs/1503.02085
68
68
Sep 21, 2013
09/13
by
D. Bard; J. M. Kratochvil; C. Chang; M. May; S. M. Kahn; Y. AlSayyad; Z. Ahmad; J. Bankert; A. Connolly; R. R. Gibson; K. Gilmore; E. Grace; Z. Haiman; M. Hannel; K. M. Huffenberger; J. G. Jernigan; L. Jones; S. Krughoff; S. Lorenz; S. Marshall; A. Meert; S. Nagarajan; E. Peng; J. Peterson; A. P. Rasmussen; M. Shmakova; N. Sylvestre; N. Todd; M. Young
texts
eye 68
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The statistics of peak counts in reconstructed shear maps contain information beyond the power spectrum, and can improve cosmological constraints from measurements of the power spectrum alone if systematic errors can be controlled. We study the effect of galaxy shape measurement errors on predicted cosmological constraints from the statistics of shear peak counts with the Large Synoptic Survey Telescope (LSST). We use the LSST image simulator in combination with cosmological N-body simulations...
Source: http://arxiv.org/abs/1301.0830v1
83
83
Sep 22, 2013
09/13
by
Z. Ivezic; J. A. Tyson; E. Acosta; R. Allsman; S. F. Anderson; J. Andrew; R. Angel; T. Axelrod; J. D. Barr; A. C. Becker; J. Becla; C. Beldica; R. D. Blandford; J. S. Bloom; K. Borne; W. N. Brandt; M. E. Brown; J. S. Bullock; D. L. Burke; S. Chandrasekharan; S. Chesley; C. F. Claver; A. Connolly; K. H. Cook; A. Cooray; K. R. Covey; C. Cribbs; R. Cutri; G. Daues; F. Delgado; H. Ferguson; E. Gawiser; J. C. Geary; P. Gee; M. Geha; R. R. Gibson; D. K. Gilmore; W. J. Gressler; C. Hogan; M. E....
texts
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We describe the most ambitious survey currently planned in the visible band, the Large Synoptic Survey Telescope (LSST). The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a large, wide-field ground-based system designed to obtain multiple images covering the sky that is visible from Cerro Pachon in Northern Chile. The current baseline...
Source: http://arxiv.org/abs/0805.2366v2
