SN 1999ga: a low-luminosity linear type II supernova?

Pastorello, A.; Crockett, R. M.; Martin, R.; Smartt, S. J.; Altavilla, G.; Benetti, S.; Botticella, M. T.; Mattila, S.; Maund, Justyn R.; Ryder, S. D.; Salvo, M.; Taubenberger, S.; Turatto, M.

doi:10.1051/0004-6361/200911993

Cited by 14 publications

(9 citation statements)

References 96 publications

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“…Given this low luminosity and the presence of narrow P-Cygni Balmer lines in follow-up spectra, Bose et al (2017) identified Gaia16cfr as a likely SN impostor. NGC 2442 was the host of the peculiar low-luminosity SN II 1999ga (Pastorello et al 2009) as well as the SN Ia 2015F and had been observed with deep, multiband, multi-epoch HST imaging by Riess et al (2016), who derived a Cepheid distance modulus of m − M = 31.51 ± 0.05 mag (20.1 ± 0.5 Mpc). Fraser et al (2017) and Kilpatrick et al (2017) identified a counterpart to Gaia16cfr in pre-outburst HST images.…”

Section: Introductionmentioning

confidence: 99%

Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr

Kilpatrick

Foley

Drout

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present multi-epoch, multi-colour pre-outburst photometry and post-outburst light curves and spectra of the luminous blue variable (LBV) outburst Gaia16cfr discovered by the Gaia satellite on 1 December 2016 UT. We detect Gaia16cfr in 13 epochs of Hubble Space Telescope imaging spanning phases of 10 yr to 8 months before the outburst and in Spitzer Space Telescope imaging 13 yr before outburst. Pre-outburst optical photometry is consistent with an 18 M F8 I star, although the star was likely reddened and closer to 30 M . The preoutburst source exhibited a significant near-infrared excess consistent with a 120 AU shell with 4 × 10 −6 M of dust. We infer that the source was enshrouded by an optically-thick and compact shell of circumstellar material from an LBV wind, which formed a pseudophotosphere consistent with S Dor-like variables in their "maximum" phase. Within a year of outburst, the source was highly variable on 10-30 day timescales. The outburst light curve closely matches that of the 2012 outburst of SN 2009ip, although the observed velocities are significantly slower than in that event. In Hα, the outburst had an excess of blueshifted emission at late times centred around −1500 km s −1 , similar to that of double-peaked Type IIn supernovae and the LBV outburst SN 2015bh. From the pre-outburst and post-outburst photometry, we infer that the outburst ejecta are evolving into a dense, highly structured circumstellar environment from precursor outbursts within years of the December 2016 event.1 Although "SN impostor" implies that these objects are not genuine corecollapse SNe and thus confuses a physical mechanism with an observational class of transients, we use this label for consistency with the existing literature. This does not imply that we think a single physical mechanism powers these objects or that none of these objects is a core-collapse SN.

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Section: Introductionmentioning

confidence: 99%

Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr

Kilpatrick

Foley

Drout

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…For griz filters, the zeropoint was calculated from magnitudes of sources in the field taken from the SkyMapper Southern Survey (Onken et al 2019). For Johnson-Cousins filters, we used the tertiary standards in NGC 2442 presented by Pastorello et al (2009). In the case of the NIR data (JHK) we used sources taken from the Two Micron All Sky Survey (2MASS; Skrutskie et al 2006).…”

Section: Photometry With the Autophot Pipelinementioning

confidence: 99%

“…AT 2016jbu is situated to the south of NGC 2442, a spiral galaxy commonly referred to as the Meathook Galaxy. NGC 2442 has hosted two other SNe including SN 1999ga, a low luminosity Type II SN (Pastorello et al 2009) and SN 2015F, a Type Ia SN (Cartier et al 2017). We mark their respective locations in Fig.…”

Section: Introductionmentioning

confidence: 99%

Photometric and spectroscopic evolution of the interacting transient AT 2016jbu (Gaia16cfr)

Brennan,

Fraser,

Johansson

et al. 2021

Preprint

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We present comprehensive, multi-wavelength observations of AT 2016jbu, an interacting transient. High cadence photometric coverage reveals that AT 2016jbu underwent significant photometric variability followed by two luminous events, the latter of which reached an absolute magnitude of M V ∼ −18.5 mag. This is similar to the transient SN 2009ip whose nature is still debated. Spectra are dominated by narrow emission lines and show a blue continuum during the peak of the second event. AT 2016jbu shows signatures of a complex, non-homogeneous circumstellar material (CSM). We see slowly evolving asymmetric hydrogen line profiles, with velocities of 500 km s −1 seen in narrow emission features from a slow moving CSM, and up to 10,000 km s −1 seen in broad absorption from some high velocity material. Similar velocities are seen in other SN 2009ip-like transients. Late-time spectra (∼ +1 year) show a lack of forbidden emission lines expected from a core-collapse supernova during the nebular phase and are dominated by strong emission from H, He i and Ca ii. Strong asymmetric emission features, a bumpy lightcurve, and continually evolving spectra suggest late time CSM interaction is inhibiting the emergence of any nebular features. We compare the evolution of Hα among SN 2009ip-like transients and find possible evidence for orientation angle effects. The light-curve evolution of AT 2016jbu suggests similar, but not identical, circumstellar environments to other SN 2009ip-like transients. In Paper II we continue the discussion of AT 2016jbu and SN 2009ip-like transients and using the data presented here, we focus on the local environment, the progenitor, and on modelling the transient itself.

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“…AT 2016jbu is located north of the southern distorted spiral arm of NGC 2442 and is still clearly present in NGC 2442 almost a year after maximum as seen in the white light image constructed from the datacube. The FOV (1 × 1 ) does however include the location of SN 1999ga (Pastorello et al 2009) as well as a luminous region in the center frame. This "Super-Bubble" has been noted by previous authors (Pancoast et al 2010), and is seen in the irregular kinematic pattern seen in the center of the FOV.…”

Section: Muse -Ing On the Local Environmentmentioning

confidence: 99%

Progenitor, environment, and modelling of the interacting transient, AT 2016jbu (Gaia16cfr)

Brennan,

Fraser,

Johansson

et al. 2021

Preprint

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In the second of two papers on the peculiar interacting transient AT 2016jbu, we present the bolometric lightcurve, identification and analysis of the progenitor candidate, as well as preliminary modelling to help elucidate the nature of this event. We identify the progenitor candidate for AT 2016jbu in quiescence, and find it to be consistent with a ∼ 20 M yellow hypergiant surrounded by a dusty circumstellar shell. We see evidence for significant photometric variability in the progenitor, as well as strong Hα emission consistent with pre-existing circumstellar material. The age of the resolved stellar population surrounding AT 2016jbu, as well as integral-field unit spectra of the region support a progenitor age of >16 Myr, again consistent with a progenitor mass of ∼20 M . Through a joint analysis of the velocity evolution of AT 2016jbu, and the photospheric radius inferred from the bolometric lightcurve, we find that the transient is consistent with two successive outbursts or explosions. The first outburst ejected a shell of material with velocity 650 km s −1 , while the second more energetic event ejected material at 4500 km s −1 . Whether the latter is the core-collapse of the progenitor remains uncertain, as the required ejecta mass is relatively low (few tenths of M ). We also place a restrictive upper limit on the ejected 56 Ni mass of <0.016 M . Using the BPASS code, we explore a wide range of possible progenitor systems, and find that the majority of these are in binaries, some of which are undergoing mass transfer or common envelope evolution immediately prior to explosion. Finally, we use the SNEC code to demonstrate that the low-energy explosion of some of these systems together with sufficient CSM can reproduce the overall morphology of the lightcurve of AT 2016jbu.

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SN 1999ga: a low-luminosity linear type II supernova?

Cited by 14 publications

References 96 publications

Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr

Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr

Photometric and spectroscopic evolution of the interacting transient AT 2016jbu (Gaia16cfr)

Progenitor, environment, and modelling of the interacting transient, AT 2016jbu (Gaia16cfr)

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