TY - JOUR
T1 - SPIRITS 15c and SPIRITS 14buu
T2 - Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163
AU - Jencson, Jacob E.
AU - Kasliwal, Mansi M.
AU - Johansson, Joel
AU - Contreras, Carlos
AU - Castellón, Sergio
AU - Bond, Howard E.
AU - Monson, Andrew J.
AU - Masci, Frank J.
AU - Cody, Ann Marie
AU - Andrews, Jennifer E.
AU - Bally, John
AU - Cao, Yi
AU - Fox, Ori D.
AU - Gburek, Timothy
AU - Gehrz, Robert D.
AU - Green, Wayne
AU - Helou, George
AU - Hsiao, Eric
AU - Morrell, Nidia
AU - Phillips, Mark
AU - Prince, Thomas A.
AU - Simcoe, Robert A.
AU - Smith, Nathan
AU - Tinyanont, Samaporn
AU - Williams, Robert
N1 - Publisher Copyright:
© 2017. The American Astronomical Society. All rights reserved..
PY - 2017/3/10
Y1 - 2017/3/10
N2 - SPitzer InfraRed Intensive Transients Survey - SPIRITS - is an ongoing survey of nearby galaxies searching for infrared (IR) transients with Spitzer/IRAC. We present the discovery and follow-up observations of one of our most luminous (M [4.5] = -17.1 ± 0.4 mag, Vega) and reddest ([3.6] - [4.5] = 3.0 ± 0.2 mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm of IC 2163 (D ≈ 35.5 Mpc). Pre-discovery ground-based imaging revealed an associated, shorter-duration transient in the optical and near-IR (NIR). NIR spectroscopy showed a broad (≈8400 km s-1), double-peaked emission line of He i at 1.083 μm, indicating an explosive origin. The NIR spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase of ≈200 days. Assuming an A V = 2.2 mag of extinction in SPIRITS 15c provides a good match between their optical light curves. The NIR light curves, however, show some minor discrepancies when compared with SN 2011dh, and the extreme [3.6]-[4.5] color has not been previously observed for any SN IIb. Another luminous (M 4.5 = -16.1 ± 0.4 mag) event, SPIRITS 14buu, was serendipitously discovered in the same galaxy. The source displays an optical plateau lasting ≳80 days, and we suggest a scenario similar to the low-luminosity Type IIP SN 2005cs obscured by A V ≈ 1.5 mag. Other classes of IR-luminous transients can likely be ruled out in both cases. If both events are indeed SNe, this may suggest that ≳18% of nearby core-collapse SNe are missed by currently operating optical surveys.
AB - SPitzer InfraRed Intensive Transients Survey - SPIRITS - is an ongoing survey of nearby galaxies searching for infrared (IR) transients with Spitzer/IRAC. We present the discovery and follow-up observations of one of our most luminous (M [4.5] = -17.1 ± 0.4 mag, Vega) and reddest ([3.6] - [4.5] = 3.0 ± 0.2 mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm of IC 2163 (D ≈ 35.5 Mpc). Pre-discovery ground-based imaging revealed an associated, shorter-duration transient in the optical and near-IR (NIR). NIR spectroscopy showed a broad (≈8400 km s-1), double-peaked emission line of He i at 1.083 μm, indicating an explosive origin. The NIR spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase of ≈200 days. Assuming an A V = 2.2 mag of extinction in SPIRITS 15c provides a good match between their optical light curves. The NIR light curves, however, show some minor discrepancies when compared with SN 2011dh, and the extreme [3.6]-[4.5] color has not been previously observed for any SN IIb. Another luminous (M 4.5 = -16.1 ± 0.4 mag) event, SPIRITS 14buu, was serendipitously discovered in the same galaxy. The source displays an optical plateau lasting ≳80 days, and we suggest a scenario similar to the low-luminosity Type IIP SN 2005cs obscured by A V ≈ 1.5 mag. Other classes of IR-luminous transients can likely be ruled out in both cases. If both events are indeed SNe, this may suggest that ≳18% of nearby core-collapse SNe are missed by currently operating optical surveys.
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U2 - 10.3847/1538-4357/aa618f
DO - 10.3847/1538-4357/aa618f
M3 - Article
AN - SCOPUS:85015926759
SN - 0004-637X
VL - 837
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 167
ER -