AstroNote 2019-160

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2019-12-28 22:24:33
Type: Object/s-Discovery/Classification
ePESSTO+ spectroscopic classification of optical transients
Authors: J. Antilen (U de Chile), T. Müller Bravo, M. Grayling, M. Smith, P. Wiseman (Southampton), C. Frohmaier (ICG Portsmouth), T.-W. Chen (Stockholm), R. Cartier (CTIO), R. Carini, S. Benetti, A. Pastorello (INAF), M. Fraser (Dublin), M. Dennefel (IAP), J. Anderson (ESO), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), M. Nicholl (Birmingham), O. Yaron (Weizmann), D. Young (QUB), I. Manulis (Weizmann), J. Tonry, L. Denneau, A. Heinze, H. Weiland, H. Flewelling (IfA, Univ. of Hawaii), B. Stalder (LSST), A. Rest (STScI), K. W. Smith, S. J. Smartt, O. McBrien, S. Srivastav (Queen's University Belfast), L. Wyrzykowski (Warsaw Observatory, Poland)
Source Group: ePESSTO+
This report includes classifications of 1 Type Ia SN around peak brightness (SN2019wkk), one Type II SN (SN2019xis) and a transient with a blue continuum (AT2019xuo). SN2019xis is of particular interest. This event is either a slowly rising SN projected behind the LMC or a highly reddened, low luminosity event in the LMC. Further observations are strongly encouraged.

ePESSTO+, the advanced Public ESO Spectroscopic Survey for Transient Objects (Smartt et al. 2015 2015A&A...579A..40S), reports the following supernova classifications.

Targets were supplied by the ATLAS survey (Tonry et al. 2018 2018PASP..130f4505T) and OGLE-IV Real-time Transient Search (Wyrzykowski et al., 2014 arxiv:1409.1095;

Observations were performed on the ESO New Technology Telescope (NTT) at La Silla on the night of 2019 December 27, using EFOSC2 and Grism 13 (3985-9315A, 18A resolution). Classifications were done using SNID (Blondin & Tonry 2007 2007ApJ...666.1024B).

The classification spectra and additional details can be obtained from (via WISeREP) and the IAU Transient Name Server.

The classified objects are listed in the Related Objects table below.

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftSourcePhase (days)RemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2019wkk [ATLAS19bdbl]03:17:10.678-19:30:18.67SN Ia0.032ATLAS003:17:10.680-19:30:18.72SN Ia0.032
TNS2019xis05:36:13.700-69:16:24.70SN II0.005OGLE-GAL-LMC517.02-374.217-667.894OGLE+70The spectrum resembles that of an evolved type II SN during the hydrogen recombination phase. Along with a red continuum, we identify Balmer lines with P Cygni profiles, Fe II, Na ID and a prominent Ca II near-IR triplet. The I-band light curve collected by the OGLE collaboration shows a slow ongoing rise lasting so far about 70 days, consistent with that of a SN 1987A-like transient. This is well matched with the presence of strong Ba II 6142A absorption in the spectrum, normally observed in faint type IIP SNe and in some SN 1987A-like events (see, e.g., Pastorello et al. 2012). The SN is in the direction of the LMC. For this reason, we cannot rule out this being a reddened SN in the LMC. However, this classification would imply a very strong reddening of over 10 magnitudes, which is not consistent with the observed colour of the SN spectrum for known reddening laws. Therefore, due to the faint luminosity with limited evidence of strong-reddening, we favour that this object is hosted in a very faint galaxy in the local Universe, projected from behind the LMC. However, while the properties of this object are more consistent with a background supernova, we cannot rule out that the object is an intrinsically faint and highly reddended SN in the LMC. Further follow-up observations are requested in order to provide a robust classification and redshift for this object.05:36:13.700-69:16:24.70Light-Echo0.0009
TNS2019xuo [ATLAS19beby]05:59:32.664-27:01:10.77Other0.107Spectrum is of a blue continuum. Further observations of this young event are encouraged.05:59:32.664-27:01:10.77