Issue |
A&A
Volume 572, December 2014
|
|
---|---|---|
Article Number | A1 | |
Number of page(s) | 9 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201424347 | |
Published online | 18 November 2014 |
An X-ray and UV flare from the galaxy XMMSL1 J061927.1-655311
1
XMM SOC, ESAC, Apartado 78, 28691 Villanueva de la Cañada,
Madrid,
Spain
e-mail:
richard.saxton@sciops.esa.int
2
Dept. of Physics and Astronomy, University of
Leicester, Leicester
LE1 7RH,
UK
3
Max-Planck Institut für Radioastronomie,
Auf dem Huegel 69, 53121
Bonn,
Germany
4
Centro de Astrobiología Depto. Astrofisica (INTA-CSIC), ESAC
campus, Apartado 78, 28691
Villanueva de la Cañada,
Spain
5
School of Physical Sciences, University of Tasmania,
7001
Hobart TAS,
Australia
6
Departamento de Astrofsica, Facultad de CC. Fsicas, Universidad
Complutense de Madrid, 28040
Madrid,
Spain
7
Research School of Astronomy and Astrophysics, Australian National
University, 2611
Canberra, ACT,
Australia
8
CSIRO Astronomy and Space Science, PO Box 76,
Epping
NSW
1710,
Australia
Received: 5 June 2014
Accepted: 22 September 2014
Aims. New high variability extragalactic sources may be identified by comparing the flux of sources seen in the XMM-Newton Slew Survey with detections and upper limits from the ROSAT All Sky Survey.
Methods. A detected flaring extragalactic source was monitored with Swift and XMM-Newton to track its temporal and spectral evolution. Optical and radio observations were made to help classify the galaxy, investigate the reaction of circumnuclear material to the X-ray flare, and check for the presence of a jet.
Results. In November 2012, X-ray emission was detected from the galaxy XMMSL1 J061927.1-655311 (a.k.a. 2MASX 06192755-6553079), a factor 140 times higher than an upper limit from 20 years earlier. Both the X-ray and UV flux subsequently fell over the following year by factors of 20 and 4, respectively. Optically, the galaxy appears to be a Seyfert I with broad Balmer lines and weak, narrow, low-ionisation emission lines, at a redshift of 0.0729. The X-ray luminosity peaks at LX ~ 8 × 1043 erg s-1 with a typical Sy I-like power-law X-ray spectrum of Γ ~ 2. The flare has either been caused by a tidal disruption event or by an increase in the accretion rate of a persistent active galactic nucleus.
Key words: galaxies: active / galaxies: individual: XMMSL1 J061927.1-655311 / X-rays: galaxies
© ESO, 2014
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.