715 citations · 3.7k across the 78 of their papers we have counts for
80 papers
Flux Dependence of the 1\,keV Soft X-ray Feature in SAX J1808.4-3658 with \textit{NICER}
Katherine Bruce, Anne M. Lohfink, Jaiverdhan Chauhan +3
We present a systematic X-ray spectral analysis of the 2019 and 2022 outbursts of the accreting millisecond pulsar SAX J1808.4-3658 with extit{NICER} with a particular emphasis on…
PACHA: Probing AGN Coronae with High-redshift AGN
Xiurui Zhao, Elias Kammoun, Marco Ajello +18
The X-ray emission of active galactic nuclei (AGN) is generally attributed to inverse Compton scattering of accretion-disk photons by hot electrons in a compact corona. In local AG…
Chandra and HST Observations of Radio-Selected (Wandering) Massive Black Hole Candidates in Dwarf Galaxies
Megan R. Sturm, Amy E. Reines, Anne M. Lohfink +6
We present Chandra X-ray Observatory and Hubble Space Telescope (HST) follow-up observations of 12 dwarf galaxies from Reines et al. (2020) that are potential hosts of radio-select…
Establishing a Connection Between the Jet and the Corona in Black Hole Low Mass X-Ray Binaries
Eric Davidson, Jaiverdhan Chauhan, Anne Lohfink +3
Low-mass black hole X-ray Binaries (LMXBs) undergo outbursts, during which their brightness increases greatly for timescales of months. The X-ray accretion and radio jet properties…
QPO signatures of disk restoration after type-I X-ray bursts from 4U~1636536
Suchismito Chattopadhyay, Jaiverdhan Chauhan, Ranjeev Misra +4
Type--I thermonuclear bursts (TNBs) from neutron star low-mass X-ray binaries (NS LMXBs) originate on the neutron star's surface from the unstable burning of the accreted material.…
Probing thermonuclear bursts and X-ray reflection features in Aql X-1 during 2024 outburst
Manoj Mandal, Sabyasachi Pal, G. K. Jaisawal +3
We report the broadband timing and spectral properties of the neutron star low-mass X-ray binary Aql X-1 during the 2024 outburst with NICER, NuSTAR, and Swift observatories. We de…
A new independent look at the galactic black hole low-mass X-ray binary distribution
Youssef Abdulghani, Anne M Lohfink, Jaiverdhan Chauhan
Investigations of the Galactic black hole low-mass X-ray binaries (BH-LMXBs) offer valuable insights into the elusive black hole population in the Milky Way. Motivated by recent te…
A Dependable Distance Estimator to Black Hole Low-Mass X-ray Binaries
Youssef Abdulghani, Anne M Lohfink, Jaiverdhan Chauhan
Black Hole Low Mass X-ray Binaries (BH-LMXBs) are excellent observational laboratories for studying many open questions in accretion physics. However, determining the physical prop…
The High Energy X-ray Probe (HEX-P): Probing the physics of the X-ray corona in active galactic nuclei
E. Kammoun, A. M. Lohfink, M. Masterson +28
The hard X-ray emission in active galactic nuclei (AGN) and black hole X-ray binaries is thought to be produced by a hot cloud of electrons referred to as the corona. This emission…
UV/Optical disk reverberation lags despite a faint X-ray corona in the AGN Mrk 335
Erin Kara, Aaron J. Barth, Edward M. Cackett +37
We present the first results from a 100-day Swift, NICER and ground-based X-ray/UV/optical reverberation mapping campaign of the Narrow-Line Seyfert 1 Mrk 335, when it was in an un…
X-ray Reverberation Mapping of Ark 564 using Gaussian Process Regression
Collin D. Lewin, Erin Kara, Daniel R. Wilkins +15
Ark 564 is an extreme high-Eddington Narrow-line Seyfert 1 galaxy, known for being one of the brightest, most rapidly variable soft X-ray AGN, and for having one of the lowest temp…
The study of thermonuclear X-ray bursts in accreting millisecond pulsar MAXI J1816-195 with NuSTAR and NICER
Manoj Mandal, Sabyasachi Pal, Jaiverdhan Chauhan +2
The millisecond pulsar MAXI J1816-195 was recently discovered in an outburst by MAXI in 2022 May. We study different properties of the pulsar using data from NuSTAR and NICER obser…
Broadband spectral analysis of Mrk 926 using multi-epoch X-ray observations
S. Chalise, A. M. Lohfink, J. Chauhan +3
The X-ray spectra of some active galactic nuclei (AGN) show a soft X-ray excess, emission in excess to the extrapolated primary X-ray continuum below 2 keV. Recent studies have sho…
High-density disc reflection spectroscopy of low-mass active galactic nuclei
L. Mallick, A. C. Fabian, J. A. García +13
The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in hi…
A Spectroscopic Angle on Central Engine Size Scales in Accreting Neutron Stars
Nicolas Trueba, J. M. Miller, A. C. Fabian +9
Analyses of absorption from disk winds and atmospheres in accreting compact objects typically treat the central emitting regions in these systems as point sources relative to the a…
The Inner Accretion Flow in the Resurgent Seyfert-1.2 AGN Mrk 817
J. M. Miller, Z. Zoghbi, M. T. Reynolds +10
Accretion disks and coronae around massive black holes have been studied extensively, and they are known to be coupled. Over a period of 30 years, however, the X-ray (coronal) flux…
Discovery of soft and hard X-ray time lags in low-mass AGNs
Labani Mallick, Daniel R. Wilkins, William N. Alston +5
The scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying phy…
Towards precision measurements of accreting black holes using X-ray reflection spectroscopy
Cosimo Bambi, Laura W. Brenneman, Thomas Dauser +14
Relativistic reflection features are commonly observed in the X-ray spectra of accreting black holes. In the presence of high quality data and with the correct astrophysical model,…
A hard look at local, optically-selected, obscured Seyfert galaxies
E. S. Kammoun, J. M. Miller, M. Koss +11
We study the X-ray spectra of a sample of 19 obscured, optically-selected Seyfert galaxies (Sy 1.8, 1.9 and 2) in the local universe (~Mpc), drawn from the CfA Seyfert…
Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
J. V. Hernández Santisteban, R. Edelson, K. Horne +33
We present results of time-series analysis of the first year of the Fairall 9 intensive disc-reverberation campaign. We used Swift and the Las Cumbres Observatory global telescope…
A Redshifted Inner Disk Atmosphere and Transient Absorbers in the Ultra-Compact Neutron Star X-ray Binary 4U 1916-053
Nicolas Trueba, J. M. Miller, A. C. Fabian +8
The very small accretion disks in ultra-compact X-ray binaries (UCXBs) are special laboratories in which to study disk accretion and outflows. We report on three sets of new (250 k…
Broad-band X-ray observation of broad-line radio galaxy 3C 109
Sulov Chalise, Anne M. Lohfink, Erin Kara +1
We present a study of the central engine in the broad-line radio galaxy 3C 109. To investigate the immediate surrounding of this accreting, supermassive black hole, we perform a mu…
A dynamic black hole corona in an active galaxy through X-ray reverberation mapping
William N. Alston, Andrew C. Fabian, Erin Kara +18
X-ray reverberation echoes are assumed to be produced in the strongly distorted spacetime around accreting supermassive black holes. This signal allows us to spatially map the geom…
X-ray spectral and flux variability of the microquasar GRS 1758-258 on timescales from weeks to years
Maria Hirsch, Katja Pottschmidt, David M. Smith +12
We present the spectral and timing evolution of the persistent black hole X-ray binary GRS 1758-258 based on almost 12 years of observations using the Rossi X-ray Timing Explorer P…