Swift observation of Nova Scorpii 2019 #1 = ASASSN-19mo
ATel #12817; K. Sokolovsky, E. Aydi, L. Chomiuk, A. Kawash, J, Strader (MSU), K. Mukai (NASA/GSFC)
on 29 May 2019; 17:38 UT
Credential Certification: Kirill Sokolovsky (kirx@scan.sai.msu.ru)
Subjects: Optical, Ultra-Violet, X-ray, Nova
Swift observed the nova ASASSN-19mo (ATel #12795, #12809) for 1.9ks
on 2019-05-27.79 UT, two weeks after discovery by the ASAS-SN
survey. The XRT detected no X-ray source at the nova position
with an upper limit of 0.005 +/-0.002 cts/s. Assuming power law
emission with the photon index of 1.7 and the total HI column
density in this direction of 5.38x10^21 cm^-2 the count rate limit
translates to the unabsorbed 0.3-10 keV flux limit
of 4.2x10^-13 ergs/cm^2/s (Kalberla et al. 2005 A&A, 440, 775).
Assuming a much lower column of 3x10^20 cm^-2 leads to
the flux limit of 2.1x10^-13 ergs/cm^2/s.
The nova is detected by Swift/UVOT having the following magnitudes
(Vega system) suggesting a high reddening, consistent with the high
reddening inferred from the optical spectroscopy (ATel #12795) and
the Galactic reddening maps (Schlafly & Finkbeiner 2011, ApJ,
737, 103):
JD Band Mag. Err.
2458631.29 UVW2 17.83 0.09
2458631.29 UVM2 >19.66
2458631.28 UVW1 16.64 0.06
2458631.28 U 15.23 0.03
2458631.28 B 14.50 0.02
2458631.29 V 13.01 0.03
The nova position measured with respect to UCAC3 (Zacharias et al.
2010 AJ, 139, 2184) stars in the UVOT field of view:
17:07:34.21 -36:08:22.2 +/-0.2" J2000
There is no Gaia DR2 counterpart within the position uncertainty.
We thank the Neil Gehrels Swift Observatory team and PI, Brad Cenko, for rapid scheduling of this ToO observation.
