XMMSL1 J070542.7-381442 is a nova
ATel #1285; M. A.P. Torres (CfA), P. G. Jonker (SRON/CfA), P. Challis (CfA), M. Modjaz (Berkeley), R. Kirshner, A. M. Read (U. Leicester), E. Kuulkers (ESA/ESAC), R. D. Saxton (ESAC)
on 17 Nov 2007; 20:39 UT
Credential Certification: Manuel Torres (mtorres@cfa.harvard.edu)
Subjects: Optical, Binary, Cataclysmic Variable, Transient
We report on optical observations of XMMSL1 J070542.7-381442. This
X-ray source has recently been discovered during XMM-Newton Slew
Survey observations (Read, Saxton & Esquej 2007, ATel #1282).
In order to identify its optical counterpart we observed the field of
XMMSL1 J070542.7-381442 on 2007 Nov 16 08:15 - 08:28 UT with the
Magellan Clay 6.5m telescope equipped with the LDSS-3 spectrograph. In
a 20 second exposure image we find a bright, saturated star within
the 8'' error circle for the X-ray location reported in ATel
#1282. The position of the optical counterpart is consistent with that
of USNO A2.0 0450-03360039 (ATel #1282).
A total of 8 spectra with exposure times ranging 1 to 60s were
acquired. The LDSS-3 setup (VPH ALL grism + 1'' slit) provided a
3700-10000 AA wavelength coverage with a dispersion of 2 AA/pix and
resolution better than 10 AA. The strongest lines in the spectra are
[0III] 5007 (blended with [OIII] 4959) followed by Halpha (FWHM ~ 2100
km/s), [OIII] 4363 (blended with Hgamma; FWHM ~ 1600 km/s) and [NII]
5755 (FWHM ~ 1800 km/s). Note that Halpha may be blended with
unresolved [NII]. NIII 4640, HeII 4686, NII 5679, HeI 5876, [FeVII]
6087, [OI] (6300,6364) and [0II] 7325 emission lines are identified in
spectra. Hbeta is stronger than HeII 4686.
From the above properties, the object is likely a nova in the auroral
phase (see e.g. Williams et al,1991,ApJ,376,721). The USNO object
is the possible progenitor of the nova.
