HUNTING FOR HIDDEN SUPERNOVAE. The Progenitor-Supernova-Remnant Connection

Transcription

1 HUNTING FOR HIDDEN SUPERNOVAE Jacob Jencson The Progenitor-Supernova-Remnant Connection Caltech Astronomy Ringberg Castle Advisor: Mansi Kasliwal July 25, 2017

2 Optical searches are blind to supernovae heavily obscured by dust. IR searches can provide a way forward, but have been hindered by detector cost and the bright IR night sky background. Transient surveys now coming online will systematically explore the dynamic infrared sky. Image Credit: NASA, ESA, A. Goobar (Stockholm University), and the Hubble Heritage Team (STScI/AURA) 2/16

3 Open Questions: 1. What is the missing SN fraction in the local universe? Can obscured SNe explain the supernova rate problem? 2. What are the progenitors of obscured SNe? Can obscured SNe explain the red supergiant problem? 3. What are the environmental conditions of obscured SNe? Do obscured SNe represent a separate SN population originating from extreme environmental conditions? 3/16

4 Previous searches have focused on extreme environments of (U)LIRGs and starbursts. 4 confirmed obscured SNe from near-ir, high-resolution searches (Cresci+ 2007, Mattila+ 2007, Kankare+ 2008, 2012). SN 2004ip in IRAS Sept. 15 NACO K s-band 16.5 x 11.5 Radio VLBI studies reveal scores of missed SNe (e.g., Perez-Torres+ 2009, Romero- Cañizales+ 2012) Sept. 15 Image subtraction with May 4 reference. No candidates from Spitzer search of nearby starbursts (PI O. Fox). Mattila /16

5 SPIRITS: A targeted search of nearby galaxies for transients in the mid-ir hours over 5 years with Spitzer Cycles ( ) 194 galaxies x 10 epochs Cycle 13 ( ) 105 galaxies x 4 epochs Sample < 20 Mpc Depth of 20 mag (Vega) at [3.6] and 19 mag at [4.5] SPIRITS Team: M Kasliwal, J Jencson, S Adams, R Lau, S Tinyanont, D Perley, F Masci, G Helou, L Armus, S Van Dyk, A Cody, M Boyer, H Bond, A Monson, J Bally, O Fox, R Williams, P Whitelock, R Gehrz, N Smith, J Johansson, E Hsiao, M Phillips, N Morell, C Contreras+ 5/16 Cadence baselines spanning one week to several years

6 SPIRITS is discovering a wide range of IR transient sources. Identified147+ transients: 37 known supernovae 17 likely novae 57 especially Red Intermediate-Luminosity Transient Events (SPRITEs; Kasliwal+ 2017) 10 luminous transients are likely to be newly discovered obscured SNe. ATels: Kasliwal+ 2014: #6644 Jencson : #7929, 8688, 8940, 9434, 10171, 10172, /16

7 Fraction of missed obscured events may be as high as 50%. 14azy 14bug 15c, 14buu Equal number of optically discovered CCSNe in our sample since 2014 Two confirmed spectroscopically, and one additional based on optical/ near-ir light curves (Jencson+ 2017; Jencson+ in prep.) Radio follow-up with VLA and ATCA ongoing 15mr 15ud 15ade 16ix 16aj 16tn & 17lb 7/16

8 SPIRITS 16tn: a highly obscured, probable CCSN at only 9 Mpc. Messier 108 Swift/UVOT UBV 2016 Aug. 29 SDSS Spitzer/IRAC [4.5] 2016 Aug. 15 Spitzer/IRAC [4.5] 2011 Feb. 7 Sci. Ref. Sub. Jencson+ in prep. 8/16

9 SPIRITS 16tn is unique in its mid-ir properties. 22 Type II Types IIb & Ib/c Type Ia [4.5] absolute magnitude (Vega) SN 2008S Ic/IIn SPIRITS 16tn Ia-CSM Iax 3 [3.6] [4.5] (Vega mag) Jencson+ in prep Time (days) Time (days) Time (days) 9/16

10 Near-IR spectrum rules out an SN Ia. 10 SN 2014J 128 days [Fe II] [Co II] [Co III] [Fe II] [Fe II] [Fe II] [Co II] [Fe II] [Co II] 15 Mg I [Fe II] +[SiI] He I Br γ SN 1998bw (Ic-BL) 60 days Normalized flux + constant SN 2005df 198 days SN 2005df 217 days SN 2005df 380 days Normalized flux + constant 10 5 SN 2010jl (IIn) 178 days SN 2011dh (IIb) 205 days SN 2013ej (IIP) 138 days 2 SPIRITS 16tn days 0 SPIRITS 16tn days Restwavelength (µm) Rest wavelength (µm) Jencson+ in prep. 10/16

11 Comparisons with Type II SN suggest AV ~ 7-9 mag. Apparent magnitude (Vega) U B V I z J H K s [3.6] [4.5] Absolute magnitude (Vega) λlλ (L ) U B B I J H K s [3.6] [4.5] SN 2004et ( ) SPIRITS 16tn t days t =140days with A V =8.4 mag, 22 8 E(B V )=2.7 mag Days since earliest detection λ (µm) Jencson+ in prep. 11/16

12 VLA and AMI radio non-detections suggest a weak event or significant absorption Type II Type IIn Type IIb Types Ib/c Lν,peak (erg s 1 Hz 1 ) SPIRITS 16tn Figure adapted from Romero- Cañizales t peak (days) (ν/5ghz) Jencson+ in prep. 12/16

13 No detection of the progenitor star in archival optical HST imaging. Jencson+ in prep. Background figure: Smartt 15 13/16

14 SPIRITS 14buu, 15c, & 17lb: 3 SNe in 4 years in IC Jencson /16

15 A combination of IR searches will be sensitive to obscured SNe at a range of distances. SPitzer InfraRed Intensive Transients Survey (SPIRITS): 3.6 and 4.5 μm targeted survey of nearby galaxies. Palomar Gattini-IR (PG-IR): Nightly J-band survey of deg 2. Expect ~ 13 SNe within 50 Mpc in 1 year. Zwicky Transient Facility (ZTF): i-band survey of 6700 deg 2 at 4-day cadence. Expect ~ 50 CCSN within 100 Mpc in 1 year. AV (mag) SPIRITS ([4.5]) PG-IR (J) ZTF (i) Distance (Mpc) Jencson+ in prep. 15/16

16 Summary Optical searches for SNe may miss events heavily obscured by dust. SPIRITS is an ongoing search for transients in the mid-ir, and has found 10 dust obscured SN candidates thus far. SPIRITS 16tn, our nearest candidate at only 9 Mpc, is a probable low-energy SN, though its mid-ir properties are unique among previously studied events. With upcoming surveys in the optical and near-ir, we can systematically search for reddened SNe and obtain spectroscopically complete samples across varying levels of obscuration. Searching for and characterizing obscured SNe will allow us to probe their significance for the missing SN fraction, and whether these events represent a separate population originating from extreme environmental conditions and progenitor systems. 16/16