Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

PNV J17545999-2122401

PNV J17545999-2122401   2020 10 02.9799*  17 54 59.99 -21 22 40.1  11.1 U             Sgr       9 0

2020 10 02.9799

Discovered by C. Jacques, C. Colesanti, C. Barreto, E. Pimentel, I. Mussi, J. Ribeiro, M. Domingues, J. Amancio, L. Amaral, P. Holvorcem, T. Napoleao on behalf of the Brazilian Transient Search - BraTS - at SONEAR Observatory, Oliveira, Brazil in three frames with 10 seconds exposure using an astrograph 280mm f/2.2 + CCD unfiltered, with magnitude 11.1 under limiting mag = 16.7. Nothing is visible at this location on the previous frames (limiting mag = 17.1) taken on 2020 Aug 16.0103 UT.

2020 10 01.6901

The object was not visible on NMW survey images obtained on 2020-10-01.6901 UT (limiting mag. 13.0). The images were obtained with a wide-field survey camera (F=135mm f/2.0 telephoto lens and ST8300M unfiltered CCD, 20sec exposure time) at Ka-Dar Observatory's TAU Station/Astrovert, Nizhny Arkhyz, Russia (MPC COD C32). --- Stanislav Korotkiy (Ka-Dar Obs./Astrovert), Kirill Sokolovsky (MSU/SAI MSU) and Olga Smolyankina (Omsk)

2020 10 02.9799

A G=19.99 source Gaia DR2 4070608344975320960 is located 1.75 arcsec North-East of the reported transient position. The Gaia source parallax is 4.97+/-1.39 mas and the Bp-Rp=1.93 color is consistent with early M type. Follow-up imaging is needed to check for the possibility that the transient is a red dwarf flare and hence Gaia DR2 4070608344975320960 is a previously unknown UV Ceti type variable star. --- Kirill Sokolovsky, Stanislav Korotkiy and Olga Smolyankina

2020 10 03.0993186

The transient is detected by ASAS-SN (Shappee et al. 2014, ApJ, 788, 48; Kochanek et al. 2017, PASP, 129, 104502) at g=12.23+/-0.02 2h 52m after the BraTS detection. Such a long duration seems unusual for a UV Ceti type flare and suggests that the object might instead be a Galactic transient affected by reddening (hence the difference between the unfiltered CCD and g-band magnitudes). No previous outbursts are seen in the ASAS-SN lightcurve https://asas-sn.osu.edu/light_curves/277ca8fe-b2aa-454c-8057-2e259729f1bd --- Kirill Sokolovsky

2020 10 03.0981

The latest ASAS-SN Sky Patrol observations (see also the link given by K. Sokolovskij) are 2020 September 29.111 UT, gmag. fainter than 15.5; October 3.098 UT, gmag. 12.16; 3.099, 12.23; 3.101, 12.25. Position end figures for Gaia DR2 are 55m00.10s in RA and 39.3" in DE (for the current epoch and equinox J2000.0). This red star is probably close to us (distance ~0.2 kpc), but the proper motion is rather small. Another red star, Gaia DR2 4070608344910091776 (Gmag. 19.99) is only 0.8" south of the reported position of the transient. The transient may be a reddened Galactic nova with an uncatalogued progenitor. Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2020 10 03.51264

Mag. 13.65(B), 11.17(V), 10.06 (R) and J2000.0 position end figures 55m 00.00s, 40.1" on a 60-s exposures taken with the 0.50-m f/6.8 reflector + CCD at iTelescope.NET, SSO, Australia. observers E. Pimentel, C. Jacques, L. Amaral, C. Colesanti, I. Mussi, J. Ribeiro, M. Domingues, J. Amancio, P. Holvorcem, T. Napoleao, C.H.Barreto on behalf of the Brazilian Transient Search (BraTS). Most likely progenitor seems to be Gaia DR2 4070608344910091776 (G mag = 18.59) which lies at only 0.75 arcsec from our measured position and whose parallax indicates a distance in the range of 1.1-1.5 kPC from us. This is rather consistent with a classic Galactic nova in a quite reddened environment.

2020 10 03.0981

Correction: The red star Gaia DR2 4070608344910091776, which has been mentioned by me (and subsequently by the BraTS team), is actually Gmag. 18.59 (and BPmag. 19.43, RPmag. 17.32); Gaia DR2 position end figures are 55m00.00s in RA and 40.9" in DE (for epoch J2015.5 and equinox J2000.0). Other designations are e.g. USNO-A2.0 0675-23344754 (Bmag. 19.6, Rmag. 17.9), USNO-B1.0 0686-0567422, PSO J175459.999-212240.808 (gmag. 20.1, rmag. 18.7, imag 18.0); GLIMPSE G007.5785+02.0523, UGPS J175459.99-212240.7, and VVV J175500.00-212240.74 —— Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2020 10 04.0983

Phptpmetry results were B=12.19, V=10.81, Rc=9.97 and Ic=9.05 with 0.43m Astrograph + FLI PL6303E CCD (T21, iTelescope.NET) at Mayhill, NM, USA. Seiichiro Kiyota (Kamagaya, Japan)

2020 10 04.422

Vmag. 10.72, Imag. 8.76, Bmag. 12.24, position end figures 55m00s.00, 39.7" observed by Andrew Pearce, Nedlands, Western Australia, using 0.43-m f/6.8 Reflector (T17, iTelescope.Net) at Siding Spring Observatory (SSO; near Coonabarabran, NSW, Australia) —— Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)