MUSE observations of a changing-look AGN – I. The reappearance of the broad emission lines
Affiliation
Univ Arizona, Steward ObservIssue Date
2019-06Keywords
galaxies: activegalaxies: individual: Mrk 590
galaxies: kinematics and dynamics
galaxies: nuclei
galaxies: Seyfert
Metadata
Show full item recordPublisher
OXFORD UNIV PRESSCitation
S I Raimundo, M Vestergaard, J Y Koay, D Lawther, V Casasola, B M Peterson, MUSE observations of a changing-look AGN – I. The reappearance of the broad emission lines, Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 1, June 2019, Pages 123–140, https://doi.org/10.1093/mnras/stz852Rights
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyCollection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Optical changing-look Active Galactic Nuclei (AGN) are a class of sources that change type within a short time-scale of years or decades. This change is characterized by the appearance or disappearance of broad emission lines, often associated with dramatic AGN continuum flux changes that are orders of magnitude larger than those expected from typical AGN variability. In this work we study for the first time the host galaxy of a changing-look AGN, Mrk 590, using high spatial resolution optical and near-infrared observations. We discover that after similar to 10 yr absence, the optical broad emission lines of Mrk 590 have reappeared. The AGN optical continuum flux however is still similar to 10 times lower than that observed during the most luminous state in the 1990s. The host galaxy shows a 4.5 kpc radius star-forming ring with knots of ionized and cold molecular gas emission. Extended ionized and warm molecular gas emission is detected in the nucleus, indicating that there is a reservoir of gas as close as 60 pc from the black hole. We observe a nuclear gas spiral between radii r similar to 0.5 and 2 kpc, which has been suggested as a dynamical mechanism able to drive the necessary gas to fuel AGN. We also discover blue-shifted and high velocity dispersion [O III] emission out to a radius of 1 kpc, tracing a nuclear gas outflow. The gas dynamics in Mrk 590 suggest a complex balance between gas inflow and outflow in the nucleus of the galaxy.ISSN
0035-8711EISSN
1365-2966Version
Final published versionSponsors
Independent Research Fund Denmark [DFF-4002-00275]; European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes [080.B-0239, 099.B-0294(A)]; Brazilian agency CNPq; Brazilian agency CAPES; Brazilian agency FAPESP; France-Brazil CAPES/Cofecub programScopus Count
Collections
Related items
Showing items related by title, author, creator and subject.
-
Planck's dusty GEMS III. A massive lensing galaxy with a bottom-heavy stellar initial mass function at z=1.5We study the properties of the foreground galaxy of the Ruby, the brightest gravitationally lensed high-redshift galaxy on the sub-millimeter sky as probed by the Planck satellite, and part of our sample of Planck's dusty GEMS. The Ruby consists of an Einstein ring of 1.4" diameter at z = 3.005 observed with ALMA at 0.1" resolution, centered on a faint, red, massive lensing galaxy seen with HST/WFC3, which itself has an exceptionally high redshift, z = 1.525 +/- 0.001, as confirmed with VLT/X-shooter spectroscopy. Here we focus on the properties of the lens and the lensing model obtained with LENSTOOL. The rest-frame optical morphology of this system is strongly dominated by the lens, while the Ruby itself is highly obscured, and contributes less than 10% to the photometry out to the K band. The foreground galaxy has a lensing mass of (3.70 +/- 0.35) x 10(11) M-Theta Magnification factors are between 7 and 38 for individual clumps forming two image families along the Einstein ring. We present a decomposition of the foreground and background sources in the WFC3 images, and stellar population synthesis modeling with a range of star-formation histories for Chabrier and Salpeter initial mass functions (IMFs). Only the stellar mass range obtained with the latter agrees well with the lensing mass. This is consistent with the bottom-heavy IMFs of massive high-redshift galaxies expected from detailed studies of the stellar masses and mass profiles of their low-redshift descendants, and from models of turbulent gas fragmentation. This may be the first direct constraint on the IMF in a lens at z = 1.5, which is not a cluster central galaxy.
-
The MOSDEF Survey: The Nature of Mid-infrared Excess Galaxies and a Comparison of IR and UV Star Formation Tracers at z ∼ 2We present an analysis using the MOSFIRE Deep Evolution Field (MOSDEF) survey on the nature of "MIR-excess" galaxies, which have star formation rates (SFRs) inferred from mid-infrared (MIR) data that are substantially elevated relative to those estimated from dust-corrected UV data. We use a sample of similar to 200 galaxies and active galactic nuclei (AGNs) at 1.40 < z < 2.61 with 24 mu m detections (rest-frame 8 mu m) from MIPS/Spitzer. We find that the identification of MIR-excess galaxies strongly depends on the methodologies used to estimate IR luminosity (L-IR) and to correct the UV light for dust attenuation. We find that extrapolations of the SFR from the observed 24 mu m flux, using luminosity-dependent templates based on local galaxies, substantially overestimate L-IR in z similar to 2 galaxies. By including Herschel observations and using a stellar-mass-dependent, luminosity-independent L-IR, we obtain more reliable estimates of the SFR and a lower fraction of MIR-excess galaxies. Once stellar-mass selection biases are taken into account, we identify similar to 24% of our galaxies as MIR excess. However, SFRH alpha is not elevated in MIR-excess galaxies compared to MIR-normal galaxies, indicating that the intrinsic fraction of MIR excess may be lower. Using X-ray-, IR-, and optically selected AGNs in MOSDEF, we do not find a higher prevalence for AGNs in MIR-excess galaxies relative to MIR-normal galaxies. A stacking analysis of X-ray-undetected galaxies does not reveal a harder spectrum in MIR-excess galaxies relative to MIR-normal galaxies. Our analysis indicates that AGN activity does not contribute substantially to the MIR excess and instead implies that it is likely due to the enhanced polycyclic aromatic hydrocarbon emission.
-
Exploring the dust content of galactic winds with Herschel – II. Nearby dwarf galaxiesWe present the results from an analysis of deep Herschel Space Observatory observations of six nearby dwarf galaxies known to host galactic-scale winds. The superior far-infrared sensitivity and angular resolution of Herschel have allowed detection of cold circumgalactic dust features beyond the stellar components of the host galaxies traced by Spitzer 4.5 mu m images. Comparisons of these cold dust features with ancillary data reveal an imperfect spatial correlation with the ionized gas and warm dust wind components. We find that typically similar to 10-20 per cent of the total dust mass in these galaxies resides outside of their stellar discs, but this fraction reaches similar to 60 per cent in the case of NGC 1569. This galaxy also has the largest metal-licity (O/H) deficit in our sample for its stellar mass. Overall, the small number of objects in our sample precludes drawing strong conclusions on the origin of the circumgalactic dust. We detect no statistically significant trends with star formation properties of the host galaxies, as might be expected if the dust were lifted above the disc by energy inputs from ongoing star formation activity. Although a case for dust entrained in a galactic wind is seen in NGC 1569, in all cases, we cannot rule out the possibility that some of the circumgalactic dust might be associated instead with gas accreted or removed from the disc by recent galaxy interaction events, or that it is part of the outer gas-rich portion of the disc that lies below the sensitivity limit of the Spitzer 4.5 mu m data.
