English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present the discovery by the SPitzer InfraRed Intensive Transients Survey(SPIRITS) of a likely supernova (SN) in NGC 3556 at only 8.8 Mpc, which,despite its proximity, was not detected by optical searches. A luminousinfrared (IR) transient at $M_{[4.5]} = -16.7$ mag (Vega), SPIRITS 16tn iscoincident with a dust lane in the inclined, star-forming disk of the host.Using IR, optical, and radio observations, we attempt to determine the natureof this event. We estimate $A_V \approx$ 8 - 9 mag of extinction, placing itamong the three most highly obscured IR-discovered SNe to date. The [4.5] lightcurve declined at a rate of 0.013 mag day$^{-1}$, and the $[3.6] - [4.5]$ colorgrew redder from 0.7 to $\gtrsim$ 1.0 mag by 184.7 days post discovery.Optical/IR spectroscopy shows a red continuum, but no clearly discerniblefeatures, preventing a definitive spectroscopic classification. Deep radioobservations constrain the radio luminosity of SPIRITS 16tn to $L_{\nu}\lesssim 10^{24}$ erg s$^{-1}$ Hz$^{-1}$ between 3 - 15 GHz, excluding manyvarieties of radio core-collapse SNe. A type Ia SN is ruled out by the observedred IR color, and lack of features normally attributed to Fe-peak elements inthe optical and IR spectra. SPIRITS 16tn was fainter at [4.5] than typicalstripped-envelope SNe by $\approx$ 1 mag. Comparison of the spectral energydistribution to SNe II suggests SPIRITS 16tn was both highly obscured, andintrinsically dim, possibly akin to the low-luminosity SN 2005cs. We infer thepresence of an IR dust echo powered by a peak luminosity of the transient of $5\times 10^{40}$ erg s$^{-1} < L_{\mathrm{peak}} < 4\times10^{43}$ erg s$^{-1}$,consistent with the observed range for SNe II. This discovery illustrates thepower of IR surveys to overcome the compounding effects of visible extinctionand optically sub-luminous events in completing the inventory of nearby SNe.

SPIRITS 16tn in NGC 3556: A heavily obscured and low-luminosity supernova at 8.8 Mpc