NTT, SPITZER, AND CHANDRA SPECTROSCOPY OF SDSSJ095209.56+214313.3: THE MOST LUMINOUS CORONAL-LINE SUPERNOVA EVER OBSERVED, OR A STELLAR TIDAL DISRUPTION EVENT?
- Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany)
- California Institute of Technology, 105-24 Robinson 1200 E. California Blvd., Pasadena, CA 91125 (United States)
- Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)
- Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel)
- I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany)
- National Astronomical Observatories, Chinese Academy of Science, A20 Datun Road, Chaoyang District, Beijing 100012 (China)
- ESA/ESAC, Apartado 78, 28691 Villanueva de la Canada, Madrid (Spain)
The galaxy SDSSJ095209.56+214313.3 (SDSSJ0952+2143 hereafter) showed remarkable emission-line and continuum properties and strong emission-line variability first reported in 2008 (Paper I). The spectral properties and low-energy variability are the consequence of a powerful high-energy flare which was itself not observed directly. Here we report follow-up optical, near-infrared (NIR), mid-infrared (MIR), and X-ray observations of SDSSJ0952+2143. We discuss outburst scenarios in terms of stellar tidal disruption by a supermassive black hole, peculiar variability of an active galactic nucleus (AGN), and a supernova (SN) explosion, and possible links between these scenarios and mechanisms. The optical spectrum of SDSSJ0952+2143 exhibits several peculiarities: an exceptionally high ratio of [Fe VII] transitions over [O III], a dramatic decrease by a factor of 10 of the highest-ionization coronal lines, a very unusual and variable Balmer line profile including a triple-peaked narrow component with two unresolved horns, and a large Balmer decrement. The MIR emission measured with the Spitzer IRS in the narrow 10-20 {mu}m band is extraordinarily luminous and amounts to L {sub 10-20{mu}}{sub m} = 3.5 x 10{sup 43} erg s{sup -1}. The IRS spectrum shows a bump around {approx}11 {mu}m and an increase toward longer wavelengths, reminiscent of silicate emission. The strong MIR excess over the NIR implies the dominance of relatively cold dust. The pre- and post-flare NIR host galaxy colors indicate a nonactive galaxy. The X-ray luminosity of L {sub x,0.1-10keV} = 10{sup 41} erg s{sup -1} measured with Chandra is below that typically observed in AGNs. Similarities of SDSSJ0952+2143 with some extreme SNe suggest the explosion of a SN of Type IIn. However, an extreme accretion event in a low-luminosity AGN or inactive galaxy, especially stellar tidal disruption, remain possibilities, which could potentially produce a very similar emission-line response. If indeed a SN, SDSSJ0952+2143 is one of the most distant X-ray- and MIR-detected SNe known so far, the most MIR luminous, and one of the most X-ray luminous. It is also by far the most luminous (>10{sup 40} erg s{sup -1}) in high-ionization coronal lines, exceeding previous SNe by at least a factor of 100.
- OSTI ID:
- 21313710
- Journal Information:
- Astrophysical Journal, Vol. 701, Issue 1; Other Information: DOI: 10.1088/0004-637X/701/1/105; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigating the Nature of the Luminous Ambiguous Nuclear Transient ASASSN-17jz
THE UNUSUAL TEMPORAL AND SPECTRAL EVOLUTION OF THE TYPE IIn SUPERNOVA 2011ht