SALT spectroscopic classification of six Gaia microlensing event candidates
ATel #15504; M. Gromadzki (Astronomical Observatory, University of Warsaw), D. Buckley (South African Astronomical Observatory), P. Zielinski (Institute of Astronomy, Nicolaus Copernicus University in Torun), P. Mroz, K. Kruszynska and L. Wyrzykowski (Astronomical Observatory, University of Warsaw)
on 6 Jul 2022; 22:11 UT
Credential Certification: Mariusz Gromadzki (marg@astrouw.edu.pl)
Subjects: Optical, Microlensing Event
We report on SALT spectroscopy of six transient events discovered by Gaia Science Alerts (Hodgkin et al. 2021). Low resolution (R = 350) SALT/RSS spectra were taken on 2022-06-10 and 2022-06-17, under the SALT Large Programme on transients (2021-2-LSP-001). The spectrum and additional details can be obtained from the IAU Transient Name Server(TNS), https://www.wis-tns.org. Classifications of targets with notes are presented below.
| Gaia Name |
IAU Name |
RA (J2000) |
Dec (J2000) |
Discovery date |
Discovery G mag |
Spectrum date |
Class |
| Gaia22atp |
AT 2022ddy |
18:42:20.19 |
02:45:26.96 |
2022-02-23 |
17.71 |
2022-06-10 | Â
Be star (1) |
| Gaia22bez |
AT 2022fnf |
18:53:31.62 |
-09:32:47.83 |
2022-03-20 |
17.32 |
2022-06-10 |
ULENS (2) |
| Gaia22bkt |
AT 2022ham |
16:47:49.21 |
-48:28:08.33 |
2022-04-01 |
13.02 |
2022-06-10 |
ULENS (3) |
| Gaia22bvq |
AT 2022kah |
13:46:05.15 |
-57:50:51.29 |
2022-04-23 |
16.52 |
2022-06-10 |
ULENS (2) |
| Gaia22bpi |
AT 2022hsm |
13:23:27.97 |
-60:01:42.56 |
2022-04-13 |
16.69 |
2022-06-17 |
ULENS (2) |
| Gaia22bvc |
AT 2022jve |
17:48:24.38 |
-45:35:49.78 |
2022-04-22 |
18.69 |
2022-06-17 |
QSO (4) | Â Â
Notes:
(1) strong Halpha emission, reddened Be star.
(2) spectra show Balmer, Mg II, Na D, Ca II and CaT absorption lines, G/K-type star/ULENS.
(3) spectrum shows TiO molecular band and faint but broad Ha line in emission and CaT lines in absorption. The light curve shows a high amplitude peak (> 4 mag) and its shape is consistent with microlensing scenario.
(4) spectrum shows broad Ly alpha and Si II at redshift of 2.3.
