94 citations · 194 across the 10 of their papers we have counts for
10 papers
Radio Monitoring of the Changing-look AGN Mrk 590 I: VLA Observations Reveal A Bow-shock Driven Radio Brightening Event
Gregory Walsh, Marianne Vestergaard, Daniel Lawther +2
Mrk 590 is a changing-look AGN (CLAGN) that slowly faded from a Seyfert Type 1 to near quiescence over a few decades before re-igniting in 2017. Monitoring in the optical/UV/X-ray…
A break in the X-ray loudness of Markarian 590: evidence for an AGN spectral state transition?
B. Palit, A. Rozanska, A. G. Markowitz +8
Using decade-long multi-band {\it Swift} observations of the changing-look AGN Markarian 590, we identify a clear break in the dependence of the X-ray loudness parameter $α_{\rm ox…
Flares in the Changing Look AGN Mrk 590. II: Deep X-ray observations reveal a Comptonizing inner accretion flow
Daniel Lawther, Marianne Vestergaard, Sandra Raimundo +2
Mrk 590 is a Changing Look AGN currently in an unusual repeat X-ray and UV flaring state. Here, we report on deep X-ray observations with XMM-Newton, NuSTAR, and NICER, obtained at…
Flares in the changing look AGN Mrk 590. I: The UV response to X-ray outbursts suggests a more complex reprocessing geometry than a standard disk
Daniel Lawther, Marianne Vestergaard, Sandra Raimundo +5
Mrk 590 is a known changing-look AGN which almost turned off in 2012, and then in 2017 partially re-ignited into a repeat flaring state, unusual for an AGN. Our \emph{Swift} observ…
MUSE observations of a changing-look AGN I: The re-appearance of the broad emission lines
S. I. Raimundo, M. Vestergaard, J. Y. Koay +3
Optical changing-look Active Galactic Nuclei (AGN) are a class of sources that change type within a short timescale of years or decades. This change is characterised by the appeara…
Quantifying the Diffuse Continuum Contribution of BLR Clouds to AGN Continuum Inter-band Delays
Daniel Lawther, Michael R. Goad, Kirk T. Korista +2
Disk reverberation mapping of a handful of nearby AGN suggest accretion disk sizes which are a factor few too large for their luminosities, apparently at odds with the standard mod…
A Hubble Space Telescope Imaging Study of Four FeLoBAL Quasar Host Galaxies
Daniel Lawther, Marianne Vestergaard, Xiaohui Fan
We study the host galaxies of four Iron Low-Ionization Broad Absorption-line Quasars (FeLoBALs) using Hubble Space Telescope imaging data, investigating the possibility that they r…
A catalog of optical to X-ray spectral energy distributions of z~2 quasars observed with Swift. I: First results
Daniel Lawther, Marianne Vestergaard, Sandra Raimundo +1
We present the Swift optical to X-ray spectral energy distributions (SEDs) of 44 quasars at redshifts z~2 observed by Swift, part of a larger program to establish and characterize…
ALMA Probes the Molecular Gas Reservoirs in the Changing-Look Seyfert Galaxy Mrk 590
J. Y. Koay, M. Vestergaard, V. Casasola +2
We investigate if the active galactic nucleus (AGN) of Mrk 590, whose supermassive black hole was until recently highly accreting, is turning off due to a lack of central gas to fu…
Constraints on the relative sizes of intervening Mg II-absorbing clouds and quasar emitting regions
Daniel Lawther, Troels Paarup, Morten Schmidt +3
Context: A significantly higher incidence of strong (rest equivalent width W_r > 1 Å) intervening Mg II absorption is observed along gamma-ray burst (GRB) sight-lines relative to t…