April 2022 - vsnet-newvar - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-newvar 9290] Gaia22alz (ATel)
by Taichi Kato 01 May '22

01 May '22

Gaia22alz (ATel) Slowest classical nova ever observed and early premaximum spectra were obtained. The Astronomer's Telegram http://www.astronomerstelegram.org ============================================================================== ATEL #15355 ATEL #15355 Title: Intriguing developments in the slowly rising Galactic optical transient Gaia22alz (AT2022bpq) Author: E. Aydi, K. V. Sokolovsky, J. Strader, L. Chomiuk, A. Kawash (MSU), J. Brink, D. A. H. Buckley (SAAO/UCT), M. Orio (UoW/INAF), J. Mikolajewska (NCAC), K. Z. Stanek, C. S. Kochanek (OSU), and B. J. Shappee (Univ. of Hawaii) Queries: aydielia(a)msu.edu Posted: 29 Apr 2022; 21:18 UT Subjects:Optical, Ultra-Violet, X-ray, Binary, Cataclysmic Variable, Nova, Star, Transient, Variables We report on multi-wavelength follow up of the slowly rising Galactic optical transient Gaia22alz (AT2022bpq), which was discovered by Gaia on 2022-02-04.2UT (https://www.wis-tns.org/object/2022bpq) Earlier follow up by Brink et al. (ATel #15270) on 2022-03-11 reported optical spectra dominated by emission lines of Balmer, He II, He I, and C IV, characterized by a FWHM of around 400-500 km/s. Based on photometry from the All-Sky Automated Survey for SNe (ASAS-SN; Shappee et al. 2014, ApJ, 788, 48S and Kochanek et al. 2017PASP, 129, 4502) the transient, which started around 2022-01-25, is still rising slowly and reached a magnitude g = 13.1 on 2022-04-29 (see below a link to the latest ASAS-SN light curve). In archival data from the Dark Energy Camera Plane Survey (DECaPS; Schlafly 2018, ApJs 234, 39) the source has a pre-outburst magnitude g = 18.9, implying a current outburst amplitude of 5.8 mag. We have obtained a series of low-, medium-, and high-resolution optical spectra on 2022-03-15, 04-03, 04-09, 04-10, 04-14, and 04-21 using the Goodman spectrograph (Clemens et al. 2004, SPIE, 5492, 331) on the 4.1-m SOAR telescope (Cerro Pachon, Chile) and the High Resolution Spectrograph (HRS; Crause et al. 2014, Proc. SPIE, 91476) mounted on the 11-m Southern African Large Telescope as part of the SALT Large Science Program on Transients. The spectrum obtained on 2022-03-15 showed similar features to the ones reported in Brink et al. (ATel #15270). However, from 2022-04-03 onwards, the spectra showed dramatic changes with the He II and C IV emission lines fading considerably, and the Balmer and He I lines developing prominent P Cygni absorption profiles at blueshifted velocities of 1700-1800 km/s, indicating the presence of an optically thick outflow. The spectra at this stage resemble those of classical novae before optical peak, but further follow up are required to determine the nature of this event. The slowly rising light curve and the spectral changes make this an interesting transient and multi-wavelength follow up are highly encouraged. Based on the absorption by diffuse interstellar bands (DIBs) and the empirical relations from Friedman et al. 2011 (ApJ 727, 33), we derive E(B-V) = 1.5 mag and Av = 4.65 mag, assuming Rv = 3.1. This is higher than the estimate of Av = 3.472 mag from the Schlafly et al. (2011, ApJ 737, 1035) Galactic reddening maps. The Neil Gehrels Swift Observatory observed Gaia22alz for 0.7ks on 2022-04-20.53 (JD 2459690.03). Swift/XRT detected no X-ray source at the position of the nova with an upper limit of 0.003 +/-0.002 cts/s. Assuming emission by a kT= 2 keV thermal plasma and an HI column density of 76.10x10^20 cm^-2 (Kalberla et al. 2005 A&A, 440, 775) this translates to an unabsorbed 0.3-10.0 keV flux limit of 7x10^-13 ergs/cm^2/s. An ultraviolet source is detected at the position of the transient by Swift/UVOT with UVW2 magnitude = 15.01 +\- 0.03 (Vega system). The ASAS-SN sky patrol light curve can be found here: https://asas-sn.osu.edu/sky-patrol/coordinate/cef95f4e-66e7-4a2b-ad65-608ca… This ATel is based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of MCTIC/LNA, the U.S. NSF's NOAO, UNC, and MSU. We also acknowledge ESA Gaia, DPAC and the Photometric Science Alerts Team (<a href="http://gsaweb.ast.cam.ac.uk/alerts">http://gsaweb.ast.cam.ac.uk/alerts</a>). We thank the Neil Gehrels Swift Observatory team and PI, Brad Cenko, for rapid scheduling these ToO observations. The Dark Energy Camera Plane Survey (DECaPS; NOAO Proposal ID 2016A-0323 and 2016B-0279, PI: D. Finkbeiner) includes data obtained at the Blanco telescope, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory (NOAO). ------------------------------------------------------------------------------ Password Certification: Elias Aydi (aydielia(a)msu.edu) https://www.astronomerstelegram.org/?read=15355 ==============================================================================

2 1

[vsnet-newvar 9291] ASASSN-22fy: new SU UMa-type dwarf nova
by Taichi Kato 30 Apr '22

30 Apr '22

ASASSN-22fy: new SU UMa-type dwarf nova Josch Hambsch has reported observations. The object showed clear superhumps on Apr. 29 (period about 0.058 d). Superhumps were not very apparent on Apr. 27.

1 0

[vsnet-newvar 9289] ASASSN-14fu: orbital period
by Taichi Kato 26 Apr '22

26 Apr '22

ASASSN-14fu: orbital period From ZTF data. Porb=0.1601606(6) d. Double maxima in one cycle (0.27 mag). There was no evidence for 0.020-0.025 d period in these data.

1 0

[vsnet-newvar 9288] 1RXS J233801.0+430852: orbital period
by Taichi Kato 26 Apr '22

26 Apr '22

1RXS J233801.0+430852: orbital period From ZTF data. Porb=0.1601353(7) d. Nearly sinusoidal 0.22 mag. The period is slightly different from the one in Weil et al. (2018) AJ 156, 231. There was no signal at 0.160400 d.

1 0

[vsnet-newvar 9287] HS1813+6122: orbital period
by Taichi Kato 26 Apr '22

26 Apr '22

HS1813+6122: orbital period From TESS data (2020 data only). Porb=0.1475122(6) d (amp. 0.05 mag). Negative superhumps were not detected. This objectis Z Cam + VY Scl. Regular outbursts in TESS data in 2020.

1 0

[vsnet-newvar 9286] SDSS J153634.42+332851.9 orbital period
by Taichi Kato 25 Apr '22

25 Apr '22

SDSS J153634.42+332851.9 orbital period Using ZTF data. Porb=0.0920302(3) d. Orbital humps 0.3 mag.

1 0

[vsnet-newvar 9285] MASTER OT J162323.48+782603.3 orbital period
by Taichi Kato 25 Apr '22

25 Apr '22

MASTER OT J162323.48+782603.3 orbital period Using ZTF data. Porb=0.0886719(2) d. Double wave per one period.

1 0

[vsnet-newvar 9284] SDSS J073817.75+285519.7 orbital period
by Taichi Kato 25 Apr '22

25 Apr '22

SDSS J073817.75+285519.7 orbital period Using ZTF data. Porb=0.2314694(8) d. Orbital hump + eclipse. UGSS+E.

1 0

[vsnet-newvar 9283] ASASSN-22gb
by Taichi Kato 25 Apr '22

25 Apr '22

ASASSN-22gb ASASSN-22gb --- ------- 8:54:25.77 -34:15:46.2 2022-04-25.16 13.58 SDSS DSS VIZIER ------- CV candidate, matches to GAIA DR2 G=21.2, g>17.0 on 2022-04-15.19, g=15.6 on 2022-04-18.93, g=13.8 on 2022-04-24.16, g=14.0 on 2022-04-25.17. ASASSN-22gb 20220415.19 <170g ASN ASASSN-22gb 20220418.93 156g ASN ASASSN-22gb 20220424.16 138g ASN ASASSN-22gb 20220425.17 140g ASN 085425.676 -341546.43 (2000.0) Gaia_DR2_5626121529556586368 plx=-(-) dismod=- pmra=-(-) pmdec=-(-) G=21.206 BP=- RP=- 085425.674 -341546.43 (2000.0) Gaia_EDR3_5626121529556586368 plx=-(-) dismod=- pmra=-(-) pmdec=-(-) G=21.099 BP=20.903 RP=20.232

1 0

[vsnet-newvar 9282] Recent post-superoutburst state of ASASSN-20pv
by Taichi Kato 24 Apr '22

24 Apr '22

Recent post-superoutburst state of ASASSN-20pv ASAS-SN data: https://asas-sn.osu.edu/sky-patrol/coordinate/0980265e-027e-4360-92e9-37d65… Fading tail and short outbursts? YYYYMMDD(UT) mag observer 20220422.0026 14.835g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220422.0038 15.042g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220422.2409 15.492g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220422.2422 15.322g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220422.2436 15.395g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220422.606 143 (Rod Stubbings) 20220423.2442 15.314g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220423.2455 15.455g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220423.2468 15.419g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220424.2435 15.497g (ASAS-SN survey (Shappee+ 2014; Kochanek+ 2017)) 20220424.592 144 (Rod Stubbings)

1 0