ORCID Profile
0000-0001-8332-0023
Current Organisation
Pontificia Universidad Católica de Chile
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Publisher: American Astronomical Society
Date: 21-04-2011
DOI: 10.1088/2041-8205/732/2/L35
Abstract: We report the discovery of a bright ( f (250 μm) mJy), multiply lensed submillimeter galaxy HERMES J105751.1+573027 in Herschel /SPIRE Science Demonstration Phase data from the HerMES project. Interferometric 880 μm Submillimeter Array observations resolve at least four images with a large separation of ∼9″. A high-resolution adaptive optics K p image with Keck/NIRC2 clearly shows strong lensing arcs. Follow-up spectroscopy gives a redshift of z = 2.9575, and the lensing model gives a total magnification of μ ∼ 11 ± 1. The large image separation allows us to study the multi-wavelength spectral energy distribution (SED) of the lensed source unobscured by the central lensing mass. The far-IR/millimeter-wave SED is well described by a modified blackbody fit with an unusually warm dust temperature, 88 ± 3 K. We derive a lensing-corrected total IR luminosity of (1.43 ± 0.09) × 10 13 L ☉ , implying a star formation rate of ∼2500 M ☉ yr −1 . However, models primarily developed from brighter galaxies selected at longer wavelengths are a poor fit to the full optical-to-millimeter SED. A number of other strongly lensed systems have already been discovered in early Herschel data, and many more are expected as additional data are collected.
Publisher: Oxford University Press (OUP)
Date: 26-07-2023
Abstract: Tidal disruption events (TDEs) occur when a star gets torn apart by a supermassive black hole as it crosses its tidal radius. We present late-time optical and X-ray observations of the nuclear transient AT2019qiz, which showed the typical signs of an optical-UV transient class commonly believed to be TDEs. Optical spectra were obtained 428, 481, and 828 rest-frame days after optical light-curve peak, and a UV/X-ray observation coincided with the later spectrum. The optical spectra show strong coronal emission lines, including [Fe vii], [Fe x], [Fe xi], and [Fe xiv]. The Fe lines rise and then fall, except [Fe xiv] that appears late and rises. We observe increasing flux of narrow H α and H β and a decrease in broad H α flux. The coronal lines have full width at half-maximum ranging from ∼150−300 km s−1, suggesting they originate from a region between the broad- and narrow-line emitting gas. Between the optical flare and late-time observation, the X-ray spectrum softens dramatically. The 0.3–1 keV X-ray flux increases by a factor of ∼50, while the hard X-ray flux decreases by a factor of ∼6. Wide-field Infrared Survey Explorer fluxes also rose over the same period, indicating the presence of an infrared echo. With AT2017gge, AT2019qiz is one of two ex les of a spectroscopically confirmed optical-UV TDE showing delayed coronal line emission, supporting speculations that Extreme Coronal Line Emitters in quiescent galaxies can be echos of unobserved past TDEs. We argue that the coronal lines, narrow lines, and infrared emission arise from the illumination of pre-existing material likely related to either a previous TDE or active galactic nucleus activity.
Publisher: American Astronomical Society
Date: 18-08-2011
Publisher: American Astronomical Society
Date: 03-05-2011
Publisher: American Astronomical Society
Date: 29-04-2011
Publisher: American Astronomical Society
Date: 14-12-2012
Publisher: Oxford University Press (OUP)
Date: 04-04-2014
DOI: 10.1093/MNRAS/STU413
No related grants have been discovered for Sam Kim.