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The SN-GRB Connection from the SN perspective

Elucidating the SN-GRB Connection: Host Galaxies and

Metallicities

Maryam ModjazMiller Postdoc Fellow/UC Berkeley

STScI, 04/30/2008

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Fellow Stellar Death Detectives

• Bob Kirshner (Former Advisor, Harvard University)

• M. Hicken, S. Blondin, P. Challis, M. Wood-Vasey, A. Friedman (Harvard/CfA)

• K. Z. Stanek, J. L. Prieto (Ohio State), T. Matheson (NOAO)

• L. Kewley (Hawaii), P. Garnavich (Notre Dame)• J. Greene (Princeton)• J. Bloom, D. Kocevski, D. Starr (UC Berkeley),

C. Blake (CfA)

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Outline: SN-GRB Connection

1) Introduction & Relevance: Definition, Massive Star Deaths SN-GRB connection, Outstanding

Question

2) Sample and Observations of SN Ib/c & GRB-SN

3) Environments of SN Ib/c and GRB-SN & the SN-GRB connection

4) Future Prospects & Conclusion

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SN Classification• Spectra:

HeI

Stripped-Envelope SN

Broad lines large expansion v large KE (1052 erg) “Hypernova”

Thermonuclear SN

Core-Collapse SN

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DEATHS OF MASSIVE STARS

• Progenitor Models of SN Ib and Ic1) Single massive (> 30 M) Wolf-Rayet (WR) stars (e.g., Maeder & Conti 2004; Woosley

et al. 1995)

Mass Loss: during MS & WR stage a) metallicity-dependent winds (Crowther

2007)

b) or LBV-type eruptions (Smith & Owocki 2006)

2) He stars (8-20 M) in binaries (Podsiadlowski et al. 2004)

• Pre-Explosion Observations of SN Ib/c: – Cannot differentiate between 1) and 2)

(Gal-Yam et al. 2005, Maund et al. 2005, Crockett et al. 2007)

– Interacting SN Ib: WR-Star w/ outburst 2 yr prior

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DEATHS OF MASSIVE STARS

• SN Rates: – 1 SN / (100 years) / (MW-galaxy)

• How common are SN Ib/c? Local rate: – ~15-20% of all SN– ~30% of CC-SN – Broad-lined SN Ic: ~5-10% of all SN Ib/c(Cappellaro et al 1999, Guetta & Della Valle 2007, Leaman et al. in

prep)

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Gamma-Ray Bursts: Extreme Explosions

• 2 “Types”: 1) Short-hard GRBs

2) Long-soft GRBs (LGRB):

- Non-thermal & dramatic variability: t/t << 1

- Relativistic outflow: ~1-1000

- Highly collimated jets: ~5-10o

Short GRB

Long

GRB

2s

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SN-LGRB Connection

• Spectroscopic ID: SN Ic-bl1) GRB980425/SN98bw z=0.0085, D=58 Mpc (Galama et

al. 1998)

2) GRB030329/SN03dh z=0.1685 (Stanek et al. 2003, Hjorth et al 2003)

3) GRB031201/SN03lw z=0.1005

(Malesani et al.2004)

4) XRF020903 z=0.25 (Soderberg et al. 2005, Bersier

et al. 2006)

5) GRB060218/SN06aj z = 0.0335, D=160 Mpc

(e.g.,Campana et al, Mirabal et al., Modjaz et al. 2006)

Stanek et al. (2003), Matheson et al. (2003)

[see also Review (Woosely & Bloom 2006)]

Nearby GRB: low-luminosity, more common (~10-103x) than cosmological GRBs (Cobb et al., Soderberg et al., Guetta & Della Valle 2006, etc)

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Collapsar Model• Core Collapse SN Ib/c• Stellar Material forms

accretion disk around rapidly rotating BH: accretion lifetime ~ GRB duration (1-103 s)

• Relativistic Jet able to leave star

(Zhang et al. 2004)

• E~1051 - 1054 erg MacFadyen, Woosley & Heger (2001)

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SN-GRB CONNECTION• What fraction?

– 20/25 of broad-lined SN Ic have NO observed GRB

viewing angle effects? - Probably NO: <10% of all

SNIb/c are off-axis GRBs (Soderberg

et al. 2006)

- Rates (Podsiadlowski 2004, Guetta & della

Valle 2007)

• What distinguishes SN with GRB from SN w/o GRB? Physical Reason?

Soderberg et al (2006)

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RELEVANCE of SN Ib & SN Ic• Deaths of Massive stars

– Constrain explosion energetics and element synthesis, progenitors and remnants

• Connection of SN Ic-bl to GRBs– What is the range of SN Ic & SN Ic-bl properties?– How aspherical are (normal) SN Ib/c explosions?

• Potential contamination of high-z SN Ia searches by SN Ic (Clocchiatti et al. 2000, Homeier 2005)

However, only a handful of well-studied objects – Matheson et al 2001 (mostly spectra) – Richardson et al. 2006 (pre-CCD SNe)

NEXT STEP: homogeneous & densely covered data set

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Outline: SN-GRB Connection

1) Introduction & Relevance2) Sample and Observations of SN

Ib/c & GRB-SN: SN - Sample (2004-2007)

Analysis: E.g. Are SN round?

3) Environments of SN Ib/c and GRB-SN & the SN-GRB connection

4) Future Prospects & Conclusion

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NEARBY CFA SN FOLLOW-UP

• Optical Spectroscopy: FAST on FLWO 1.5m – 3–4 spectra/night, ~300 spectra/year– Reduced in the same manner

• Optical Photometry (UBVr’i’): FLWO 1.2m– 3-4 SN/night, templates, standard star obs

• NIR Photometry (JHKs): PAIRITEL 1.3m– 3-4 SN/night

• Late-time (>3 months) Spectra: – MMT (AZ), Magellan (Chile),– Gemini-North (Hawaii, GN-2005B/2006A)

1.5m 1.2m 1.3m

6.5m MMT

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Representative Data

t

Sample (> 10 epochs of Optical Photometry or Spectra):

-11 SN Ib/IIb-10 SN Ic-1 GRB-SN

1) Doubles world supply of well-observed SN Ib/c2) Peculiar objects: 05bf, 06jc

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Photometry: 2004-2007

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Theory: Light curves Spectra

t

56Ni

FluxKE

Mejecta

SN Ejecta:

v(r)r

Cre

dit:

S. B

lond

in

LC width ejecta KE-3 Line width ejecta KE1/2

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SN2006aj/GRB060218- z = 0.0335, Weak GRB Afterglow- short rise time (10 days)

Modjaz et al. 2006

98bw

Time- stretched 98bw

GRB-SN

Diversity in SN-GRBs !!

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Modeling & Implications of GRB060218/SN2006aj

Mazzali et al. (2006): Ek ~ 2 x 1051 erg, M ~ 25 M

Dat

a fr

om P

ian

et a

l (20

06)

Low-z GRB(-SN): low-lum., larger , more common (~10-103x) than cosmological GRBs

(Cobb et al., Soderberg et al., Guetta & Della Valle, etc)

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Analysis: a) Distribution of MV

1) Large range of mags (~4 mags)

2) SN Ib/IIb on average fainter than SN Ic

3) Broad-lined SN Ic not necessarily more luminous than normal SN Ib/c

SN Ib/IIb

SN Ic

SN Ic-bl

MV(@peak)

Richardson et al. (2006) & my sample

SN Ia (@ peak)

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Analysis: Luminosity & LC

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et a

l. in

pre

p

2) GRB-SN & broad-lined SN Ic have similar spectra GRB-SN appear more luminous (~2 mag)

1) No Luminosity - LC shape relationship for SN Ic

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Late-time Line Diagnostics

Probe deeper into SN ejecta than early-time spectra:

1) Line Ratios: state of core before explosion

(Foley et al. 2003, Maeda et al. 2005)

2) Line shape: geometry of explosion (Mazzali et al. 2005, Maeda et al. 2006,

Valenti et al, in prep)

[O I] 6300,6363

[Ca II] 7319,7324

[Mg I 4571

SN 2004gk (SN Ic)

- GRB

SN 2003jd (SN Ic-bl) : Off-axis GRB? (Mazzali et al. 2005)

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Late-time Spectra (~10 SN Ib/c)

Modjaz, Kirshner, & Challis (2008b)

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Asphericities are common in SN Ib/c

- Oxygen ring ejection in SNR E0102.2-7219 (Tuohy & Dopita 1983, Blair et al. 2000)

Gerardy et al. (2002)

Maeda et al. (2008)Modjaz, Kirshner, & Challis (2008b)

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Outline: SN-GRB Connection

1) Introduction & Relevance:2) Sample and Observations of SN

Ib/c & GRB-SN3) Environments of SN Ib/c and GRB-

SN & the SN-GRB connection:Blue light (proxy for mass)

Abundance 4) Future Prospects & Conclusion

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SN-GRB distinction: Environs

Fruchter et al (2006):

- high-z GRB (0.2 < z < 1.0)

-“GRBs are concentrated on the brightest regions of their hosts.”

SN II (Non-SN Ia)

LGRB

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Environmental Clues

Kelly, Kirshner, & Pahre (2008, submitted)

SN Ic-bl

SN Ic

LGRB

Local SN Ic and GRB have similar locations compared to host galaxy light

Fruchter et al (2006)

-Similar (large) progenitor masses

- Additional ingredient needed for GRB production

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GRB Host galaxies

SN II (Non-SN Ia)

LGRB

• Fruchter et al. (2006):– GRB hosts are less

luminous & smaller than SN II hosts

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Host galaxies of LGRBs

• Low-metallicity, subluminous host galaxies: – @ low-z (Sollerman et al. 2005, Gorosabel

et al 2005, Modjaz et al. 2006, Thoene et al 2007,Wiersama et al 2007 )

– Possibly @ high-z(Le Floc’h et al 2003, Fruchter et al.

2006)

Stanek, .., Modjaz et al (2007)

Nearby GRBs not unbiased tracers of star formation

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Stellar Evolution @ low Z• Progenitor Stars of GRB:

– Rotating massive stars @ low Z with Taylor-Spruit Dynamo

– High Angular momentum in core– Removal of H:

• Mixing of H (Hirschi et al. 2005)

• Binary interaction

– Massive core(MacFadyen & Woosley1999; Yoon & Langer 2005; Heger &

Woosley 2006)

• Prediction: SN without GRB have higher Z

Ingredients for SN-GRB

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Metallicities of Broad-lined SN Ic

• Sample: 12 broad-lined SN Ic w/o GRBs (z < 0.15)

• Data: Own & Archival (SDSS)

• Stellar Light Removal• Oxygen Abundance

estimates from strong line diagnostics (Kewley & Dopita 02 & others)

• Central & SN-position measurements

• Uncertainty budget

Modjaz et al. (2008)

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Local abundances of GRB-SN and broad-lined SN Ic

Local SDSS galaxies (Tremonti et al 2004) in KD02 scale

Modjaz et al (2008)

Z-Offset not due to selection effects

Importance of galaxy-impartial SN surveys, e.g.,

PanSTARRS!

SMC

LMC

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Z-Offset independent of Z-Diagnostic

KS-Test: 3% 4% 3%

(Pettini & Pagel, Te )(McGaugh 91)(McGaugh 91) (Pettini & Pagel, Te )

KS-Test: 3% 4% 3%

SN w/o GRBSN w/ GRB

(Kewley & Dopita 02)

“cut-off metallicity”: 0.2- 0.6 Z

Most favored:

0.3 Z

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Metallicities Via Absorption @ higher Redshift

Prochaska et al (2007): No low-Z preference of GRB-DLA vs. QSO-DLA

Not comparing same element!

Need NIR spectraNIR spectra for high-z GRBs to observe emission lines

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Conclusions

• SN-GRB Connection:– Association between core-collapse SN (broad-lined SN Ic

w/o H and He) and LGRBs well-established– BUT: Why do some SN have GRBs and some not?

• Spectroscopic & photometric dataset for SN Ib and Ic is comprehensive, extensive & well time sampled

• Asphericity in (even) normal SN IIb/Ib/Ic & not only in SN-GRB

• Sites of broad-lined SN Ic (w/o GRB): higher oxygen abundance than those of SN-GRB: low Z key-factor for nearby GRB-SN

• FUTURE: - GRBs as beacons for galaxies - Environments of SN

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Future Prospects

• Look for Trends between SN Properties & Abundances

(Woosley & Janka 2005)

• Differentiate between Progenitor Models of SN Ib/c:1) Single massive (> 30 M) Wolf-

Rayet (WR) stars

Mass Loss: during MS & WR stage via metallicity-dependent winds PREDICTION: ZSNIc > ZSNIb

2) He stars (8-20 M) in binaries

PREDICTION: ZSNIc ~ ZSNIb

SN Ic ?SN Ib ?

Chemical abundances for all SN Ib & SN Ic @ the explosion sites

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Bridging low & high redshift

Savaglio et al. (2008, submitted)

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MAPPING between SN-type & Progenitor

• Attempts: a) Theoretical b) Observational

Heger et al (2003): Single non-rotating StarsMprog (Msol)

Met

alli

c it y

Gal-Yam et al. (2006)

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Theoretical Modeling

• Ken Nomoto & collaborators

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Spectral Library

• Spectra & Lightcurves: Spectral Sequence

• SN identification: – SN Ic very similar to SN Ia ! All Spectra

with phase info used in SNID (Blondin & Tonry 2007)

• SN identifications via email & available at http://cfa-www.harvard.edu/cfa/oir/Research/supernova/RecentSN.html

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SN Ia vs. SN Ic

At maximum light At two weeks past maximum

Blondin & Tonry (2007)

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SN Ia vs. SN Ic

At maximum light At two weeks past maximum

Blondin & Tonry (2007)

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Line Transitions

Grotrian diagram for Fe II (b-b only)Gehren et al. 2001

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Late-time Data: a) SN2005bfBlueshift: ~2000 km/sOI: double-peaked

H: not blue-shifted, FWHM = 9000 km/s

-0.2 - 0.3 Msun for thick shell (if v = 0.2-0.5 v)

- at R=2x1016 cm

-Predicted: LX~4 x 1039 erg s-1

-From WR Wind?

Moxy> 0.1- 1.1 Msun

Assuming:-T~ 3000-4500 K-ne ~106 - 108 cm-3