AstroNote 2019-106

Primary tabs

2019-10-19 09:34:58
Type: Object/s-Discovery/Classification
Swift observations and spectroscopic classification of OGLE19qem as a Type IIn supernova
Authors: M. Gromadzki, N. Ihanec, S. Kozlowski, L. Wyrzykowski (Uni. of Warsaw), I. Arcavi, B. Trakhtenbrot (Tel Aviv University), D. Buckley (SAAO), C. Ricci (UDP), E. Kara (MIT)
Here we present Swift observations and spectroscopic classification of OGLE19qem. The object was not detected in X-rays. UVOT colours suggests a temperature around 7000 K, while the spectral features and their evolution indicate that this transient is a Type IIn supernova.
The optical transient OGLE19qem was detected on 2019-09-12 in the galaxy GALEXASC J060344.94-642234.4, about 2.0 arcsec from host center (PA~164deg), at a magnitude I=20.98+/-0.28. Within a month its brightness in the I-band reaches 16.06+/-0.01 magnitude ( The SALT spectrum obtained on 2019-09-21 shows a blue continuum superimposed by Balmer, HeI, and [O III] emission lines, as well as a likely blend of HeII + NIII lines around 4660A. An additional, higher-quality spectrum taken on 2019-10-07 shows a similar set of emission lines, except for the HeII + NIII blend at ~4660A, which has disappeared. Swift observed OGLE19qem for 1.9ks on 2019-09-29. Swift/XRT detected no X-ray source at the position of the transient with an upper limit of 6.0e-14 ergs/cm^2/s at 0.5-2keV. An ultraviolet source is detected at the position of the transient with the following UVOT magnitudes (Vega system): V 16.21 0.07 B 16.39 0.04 U 15.39 0.10 UVW1 15.06 0.04 UVW2 15.26 0.04 UVM2 15.15 0.04 Taking into account the Galactic reddening of E(B-V)=0.05 (Schlafly et al. 2011 ApJ, 737, 103) the ultraviolet magnitudes correspond to the colour temperature of about 7000 K. The spectral evolution and the SED of the transient suggest that OGLE19qem is a Type IIn supernova. We thank the Swift team for execution of this observations. We acknowledge the OGLE-IV Transient Detection System presented in ATel #4495; Kozlowski et al. 2013, AcA, 63, 1, 1; Wyrzykowski et al. 2014, AcA, 64, 197
Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2019qem [OGLE19qem]06:03:45.000-64:22:36.00SN IIn0.042GALEXASC J060344.94-642234.40.04206:03:45.010-64:22:35.94SN IIn0.042