149 citations · 497 across the 16 of their papers we have counts for
16 papers
The Halo21 Absorption Modeling Challenge: Lessons From "Observing" Synthetic Circumgalactic Absorption Spectra
Zachary Hafen, Sameer, Cameron Hummels +7
In the Halo21 absorption modeling challenge we generated synthetic absorption spectra of the circumgalactic medium (CGM), and attempted to estimate the metallicity, temperature, an…
A Complex Multiphase DLA Associated with a Compact Group at z=2.431 Traces Accretion, Outflows, and Tidal Streams
Nikole M. Nielsen, Glenn G. Kacprzak, Sameer +4
As part of our program to identify host galaxies of known z=2-3 MgII absorbers with the Keck Cosmic Web Imager (KCWI), we discovered a compact group giving rise to a z=2.431 DLA wi…
Probing the physicochemical properties of the Leo Ring and the Leo I group
Sameer, Jane Charlton, Glenn Kacprzak +6
We present an absorption line study of the physical and chemical properties of the Leo HI Ring and the Leo I Group as traced by 11 quasar sightlines spread over a 600 kpc X 800 kpc…
Improving blazar redshift constraints with the edge of the Ly forest: 1ES 1553+113 and implications for observations of the WHIM
J. Dorigo Jones, S. D. Johnson, Sowgat Muzahid +6
Blazars are some of the brightest UV and X-ray sources in the sky and are valuable probes of the elusive warm-hot intergalactic medium (WHIM; K). However, man…
Using cosmological simulations and synthetic absorption spectra to assess the accuracy of observationally derived CGM metallicities
Rachel Marra, Christopher W. Churchill, Caitlin Doughty +6
We used adaptive mesh refinement hydrodynamic cosmological simulations of a Milky Way-type galaxy and a Dwarf galaxy and generated synthetic quasar absorption-line spec…
A partial Lyman limit system tracing intragroup gas at towards HE1003+0149
Anand Narayanan, Sameer, Sowgat Muzahid +6
We present an analysis of the galaxy environment and physical properties of a partial Lyman limit system at z = 0.83718 with HI and metal line components closely separated in redsh…
Solar-Metallicity Gas in the Extended Halo of a Galaxy at
Jayadev Pradeep, Sriram Sankar, T. M. Umasree +5
We present the detection and analysis of a weak low-ionization absorber at along the blazar sightline PG~, using spectroscopic data from both /COS and…
Broad absorption line disappearance/emergence in multiple ions in a weak emission-line quasar
Weimin Yi, M. Vivek, W. N. Brandt +9
We report the discovery of disappearance of Mg ii, Al iii, C iv, and Si iv broad absorption lines (BALs) at the same velocity, accompanied by a new Civ BAL emerging at a higher vel…
X-ray and multi-epoch optical/UV investigations of BAL to non-BAL quasar transformations
Sameer, W. N. Brandt, S. Anderson +10
We report on an X-ray and optical/UV study of eight Broad Absorption Line (BAL) to non-BAL transforming quasars at 1.7-2.2 over 0.29-4.95 rest-frame years with at lea…
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using its General Relativity Centenary Flare: Improved Orbital Parameters
Lankeswar Dey, M. J. Valtonen, A. Gopakumar +5
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show…
Optical variability in IBL S5 0716+714 during the 2013-2015 outburst
Navpreet Kaur, Kiran S. Baliyan, S. Chandra +2
With an aim to explore optical variability at diverse timescales in BL Lac source S5 0716+714, it was observed for 46 nights during 2013 January 14 to 2015 June 01 when it underwen…
Stochastic modeling of multiwavelength variability of the classical BL Lac object OJ 287 on timescales ranging from decades to hours
A. Goyal, L. Stawarz, S. Zola +109
We present the results of our power spectral density analysis for the BL Lac object OJ\,287, utilizing the {\it Fermi}-LAT survey at high-energy -rays, {\it Swift}-XRT in X-rays…
MAGIC observations of variable very-high-energy gamma-ray emission from PKS1510-089 during May 2015 outburst
Julian Sitarek, Josefa Becerra González, Vandad Fallah Ramazani Elina Lindfors +11
PKS1510-089 is a flat spectrum radio quasar located at a redshift of 0.36. It is one of only a few such sources detected in very-high-energy (VHE, >100 GeV) gamma rays. Though PKS1…
Multi-wavelength study of flaring activity in HBL 1ES 1959+650 during 2015-16
Navpreet Kaur, S. Chandra, Kiran S Baliyan +2
We present the results from a multiwavelength study of the flaring activity in HBL, 1ES 1959+650, during January 2015-June 2016. The source underwent significant flux enhancements…
Optical intra-day variability in 3C 66A: 10 years of observations
Navpreet Kaur, Sameer, Kiran S. Baliyan +1
We present results based on the observations of the blazar 3C 66A from 2005 November 06 to 2016 February 14 in the BVR and I broadbands using 1.2m telescope of the Mt. Abu InfraRed…
Primary black hole spin in OJ287 as determined by the General Relativity centenary flare
M. J. Valtonen, S. Zola, S. Ciprini +87
OJ287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts which are predictable in a binary black hole model. The model predicted a majo…