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|Title:||AT 2017be - a new member of the class of intermediate-luminosity red transients||Authors:||Cai, Y. -Z.
BOTTICELLA, MARIA TERESA
ELIAS DE LA ROSA, NANCY DEL CARMEN
Howell, D. A.
Reynolds, T. M.
Stritzinger, M. D.
|Issue Date:||2018||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||480||Issue:||3||First Page:||3424||Abstract:||We report the results of our spectrophotometric monitoring campaign for AT 2017be in NGC 2537. Its light curve reveals a fast rise to an optical maximum, followed by a plateau lasting about 30 d, and finally a fast decline. Its absolute peak magnitude (M<SUB>r</SUB> ≃ -12 mag) is fainter than that of core-collapse supernovae, and is consistent with those of supernova impostors and other intermediate-luminosity optical transients. The quasi-bolometric light-curve peaks at ∼2 × 10<SUP>40</SUP> erg s<SUP>-1</SUP>, and the late-time photometry allows us to constrain an ejected <SUP>56</SUP>Ni mass of ∼8 × 10<SUP>-4</SUP> M<SUB>☉</SUB>. The spectra of AT 2017 be show minor evolution over the observational period, a relatively blue continuum showing at early phases, which becomes redder with time. A prominent H α emission line always dominates over other Balmer lines. Weak Fe II features, Ca II H&K, and the Ca II NIR triplet are also visible, while P-Cygni absorption troughs are found in a high-resolution spectrum. In addition, the [Ca II] λλ7291, 7324 doublet is visible in all spectra. This feature is typical of intermediate-luminosity red transients (ILRTs), similar to SN 2008S. The relatively shallow archival Spitzer data are not particularly constraining. On the other hand, a non-detection in deeper near-infrared HST images disfavours a massive Luminous Blue Variable eruption as the origin for AT 2017be. As has been suggested for other ILRTs, we propose that AT 2017be is a candidate for a weak electron-capture supernova explosion of a superasymptotic giant branch star, still embedded in a thick dusty envelope.||URI:||http://hdl.handle.net/20.500.12386/27507||URL:||https://academic.oup.com/mnras/article/480/3/3424/5063576||ISSN:||0035-8711||DOI:||10.1093/mnras/sty2070||Bibcode ADS:||2018MNRAS.480.3424C||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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checked on Oct 27, 2020
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