X-ray emission of nova M31N 2014-02a detected with Swift
ATel #6374; R. Sturm (MPE), M. Henze (ESAC/ESA), J. Greiner (MPE), W. Pietsch (MPE), F. Haberl (MPE)
on 7 Aug 2014; 11:51 UT
Credential Certification: Richard Sturm (firstname.lastname@example.org)
Subjects: X-ray, Nova, Transient
Referred to by ATel #: 6564
We report the discovery of an X-ray transient in monitoring observations of the central region of the Andromeda Galaxy (M 31)
with the X-ray telescope on board the Swift satellite.
The source is located at
RA = 00:43:26.66 Dec = +41:23:30.8 (J2000, total coordinate uncertainty 4.2", 90% confidence level).
The energy of the bulk of the detected photons is below 1 keV, pointing to a super-soft X-ray spectrum.
Light-curve information is given in the table below, including 3σ upper limits.
ObsID Exp Date Rate
[ks] (UT) [10-3 ct s-1]
00032702058 3.6 2014-06-11.82 <6.3
00032702059 3.3 2014-06-19.01 <6.1
00032702060 3.6 2014-06-27.00 <3.5
00032702061 3.9 2014-07-05.67 5.1±1.5
00032702062 4.2 2014-07-13.74 2.1±1.0
00032702063 4.0 2014-07-21.00 <6.8
00032702066 3.4 2014-08-01.19 5.4±1.7
The position of the X-ray source is in agreement with the M 31 nova 2014-02a (ATel #5844
) having an angular separation of 2.7".
It was classified as a He/N nova with a high expansion velocity (ATel #5852
These novae tend to have short X-ray turn on times and harder X-ray spectra compared to FeII novae (Henze et al. 2014, A&A, 563A, 2),
which is consistent with the X-ray emission reported here.
We first detected the nova in X-rays about 150 days after the optical discovery.
This is a relatively short turn-on time of the supersoft X-ray emission (cf. Henze et al. 2014).
The X-ray light curve might suggest variability. A variable flux during the early stages of the supersoft X-ray phase has been observed for several M 31 and Galactic novae (e.g. ATels #4727
We would like to thank the Swift Team for making these observations possible, in particular N. Gehrels, the duty scientists, as well as the science planners.