HUNTING FOR HIDDEN SUPERNOVAEJacob Jencson The Progenitor-Supernova-Remnant Connection Caltech Astronomy Ringberg CastleAdvisor : Mansi Kasliwal July 25, 2017

July 25, 2017Jacob Jencson 2/16

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)

July 25, 2017Jacob Jencson 3/16

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?

July 25, 2017Jacob Jencson 4/16

Previous searches have focused on extreme environments of (U)LIRGs and starbursts.

SN 2004ip in IRAS 18293-3413

16.5’’ x 11.5’’

2004 Sept. 15NACO Ks-band

Image subtraction with May 4 reference.

4 confirmed obscured SNe from near-IR, high-resolution searches (Cresci+ 2007, Mattila+ 2007, Kankare+ 2008, 2012).

Radio VLBI studies reveal scores of missed SNe (e.g., Perez-Torres+ 2009, Romero-Cañizales+ 2012).

No candidates from Spitzer search of nearby starbursts (PI O. Fox). Mattila+ 2007

2004 Sept. 15

July 25, 2017Jacob Jencson 5/16

SPIRITS: A targeted search of nearby galaxies for transients in the mid-IR.1410 hours over 5 years with Spitzer

Cycles 10-12 (2014-2016)194 galaxies x 10 epochs

Cycle 13 (2017-2018)105 galaxies x 4 epochs

Sample < 20 Mpc

Depth of 20 mag (Vega) at [3.6] and 19 mag at [4.5]

Cadence baselines spanning one week to several years

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+

July 25, 2017Jacob Jencson 6/16

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+ 2015-17: #7929, 8688, 8940, 9434, 10171, 10172, 10488

July 25, 2017Jacob Jencson 7/16

Fraction of missed obscured events may be as high as 50%.

14azy 14bug 15c, 14buu

15mr 15ud 15ade

16aj16ix 16tn

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

& 17lb

July 25, 2017Jacob Jencson 8/16

SPIRITS 16tn: a highly obscured, probable CCSN at only 9 Mpc.

Jencson+ in prep.

Spitzer/IRAC [4.5] 2016 Aug. 15

Spitzer/IRAC [4.5] 2011 Feb. 7

Sci. Ref. Sub.

Messier 108

SDSS

Swift/UVOT UBV 2016 Aug. 29

−22

−20

−18

−16

−14

−12

[4.5]a

bsol

ute

mag

nitu

de(V

ega)

Type II

Ic/IIn

Types IIb & Ib/c Type Ia

Ia-CSM

Iax

0 100 200 300 400Time (days)

−1

0

1

2

3

[3.6]−

[4.5](

Vega

mag

)

0 100 200 300 400Time (days)

0 100 200 300 400Time (days)

July 25, 2017Jacob Jencson 9/16

SPIRITS 16tn is unique in its mid-IR properties.

Jencson+ in prep.

SPIRITS 16tn

SN 2008S

July 25, 2017Jacob Jencson 10/16

Near-IR spectrum rules out an SN Ia.

1.4 1.6 1.8 2.0 2.2 2.4Rest wavelength (µm)

0

5

10

15

Normalized

flux+constant

SN 1998bw(Ic-BL)60 days

SN 2010jl (IIn)178 days

SN 2011dh (IIb)205 days

SN 2013ej (IIP)138 days

SPIRITS 16tn136 - 218 days

He IMg I [Fe II]+ [Si I]

Br γ

1.50 1.55 1.60 1.65 1.70 1.75 1.80Restwavelength (µm)

0

2

4

6

8

10

Normalized

flux+constant

SN 2014J128 days

SN 2005df198 days

SN 2005df217 days

SN 2005df380 days

SPIRITS 16tn136 - 229 days

[Fe

II]

[Co

II]

[Co

III]

[Fe

II] [Fe

II]

[Fe

II] [C

oII

][F

eII

]

[Co

II]

Jencson+ in prep.

July 25, 2017Jacob Jencson 11/16

Comparisons with Type II SN suggest AV ~ 7 - 9 mag.

−16

−14

−12

−10

−8

−6

Abs

olut

em

agni

tude

(Veg

a)

−200 −100 0 100 200 300Days since earliest detection

12

14

16

18

20

22

24

App

aren

tmag

nitu

de(V

ega)

U

B

V

I

z

J

HKs

[3.6]

[4.5]

0.5 1.0 5.0λ (µm)

104

105

106

107

λLλ

(L⊙

)

SPIRITS 16tnt ∼ 40–125 days

SN 2004et×(3.7× 10−2)

t = 140 days

with AV = 8.4 mag,

E(B − V ) = 2.7 mag

U B BB I J H Ks [3.6] [4.5]

Jencson+ in prep.

July 25, 2017Jacob Jencson 12/16

VLA and AMI radio non-detections suggest a weak event or significant absorption.

100 101 102 103

tpeak (days)× (ν/5 GHz)

1024

1025

1026

1027

1028

1029

Lν,peak(erg

s−1Hz−

1 )

Type IIType IInType IIbTypes Ib/cSPIRITS 16tn

Figure adapted from Romero-Cañizales+ 14.

Jencson+ in prep.

July 25, 2017Jacob Jencson 13/16

No detection of the progenitor star in archival optical HST imaging.

Jencson+ in prep.

Background figure: Smartt 15

July 25, 2017Jacob Jencson 14/16

SPIRITS 14buu, 15c, & 17lb: 3 SNe in 4 years in IC 2163.

Jencson+ 2017

100

200SPIRITS ([4.5])

2 5 10 20 50 100 200Distance (Mpc)

0

5

10

15

20

25A

V(m

ag) PG-IR (J)

ZTF (i)

July 25, 2017Jacob Jencson 15/16

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

15000 deg2.• Expect ~ 13 SNe within 50

Mpc in 1 year.

Zwicky Transient Facility (ZTF):

• i-band survey of 6700 deg2 at 4-day cadence.

• Expect ~ 50 CCSN within 100 Mpc in 1 year.

Jencson+ in prep.

July 25, 2017Jacob Jencson 16/16

SummaryOptical 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.