Swift observation of Nova Cassiopeiae 2020 = TCP J00114297+6611190 before peak optical brightness
ATel #13919; Kirill Sokolovsky, Laura Chomiuk, Adam Kawash, Elias Aydi, Jay Strader (MSU), Koji Mukai (NASA/GSFC), Kwan-Lok Li (NTHU), Stella Kafka (AAVSO), Sergey Karpov (Institute of Physics, Prague), Stanislav Korotkiy (Ka-Dar Obs./Astrovert), Krzysztof Stanek, Christopher Kochanek (OSU), Benjamin Shappee (UoHawaii)
on 6 Aug 2020; 10:43 UT
Credential Certification: Kirill Sokolovsky (kirx@scan.sai.msu.ru)
Subjects: Optical, X-ray, Nova
Nova Cas 2020 (TCP J00114297+6611190), a Fe II type classical nova,
was discovered on 2020-07-27.9302 UT by S. Korotkiy (ATel #13903,
#13904, #13905). The follow-up photometry was collected by
FRAM-ORM 0.25m telescope (Janecek et al. 2019, EPJWC 19702008),
ASAS-SN (Shappee et al. 2014, ApJ, 788, 48), AAVSO observers
and the NMW camera (Sokolovsky et al. 2014, ASPC, 490, 395)
that was used to discover the nova. After an initial fading from
12.87 +/-0.05 (discovery image, unfiltered with V zero-point;
hereafter "CV") to CV=13.32 +/-0.06 on 2020-07-28.8812,
the nova showed gradual brightening, possibly
reaching its peak CV=11.55 +/-0.02 around 2020-08-05.7995. Filtered
photometry collected by FRAM-ORM on 2020-08-05.0138 shows
the near-peak magnitude V=11.84 +/-0.01, ASAS-SN observed the nova
at g=12.53 +/-0.01 on 2020-08-06.2779. Long time-series observations
with a 80mm refractor + ST8300M CCD camera on 2020-07-28, 29 and
2020-08-03, 04, 05 show only smooth brightness variations
on timescales of hours with no variations on shorter timescales.
We observed Nova Cas 2020 with Swift for 1.4ks on
2020-08-02.888 UT. Swift/XRT detected no X-ray source at
the position of the nova with a one sigma upper limit
of 0.0008 cts/s. Assuming power law emission with the photon index
of 2 and HI column density of 8.2x10^21 cm^-2 (Kalberla et al. 2005
A&A, 440, 775) this translates to the unabsorbed 0.3-10 keV flux
limit of 7x10^-14 ergs/cm^2/s. Simultaneous observations with
Swift/UVOT detected the nova at V=12.55 +/-0.02 (Vega system).
We thank the Neil Gehrels Swift Observatory team and PI,
Brad Cenko, for scheduling these ToO observations and
the AAVSO observers for their valuable contributions.
Lightcurve of Nova Cas 2020
