the sn-grb connection from the sn perspective
DESCRIPTION
Elucidating the SN-GRB Connection: Host Galaxies and Metallicities. The SN-GRB Connection from the SN perspective. Maryam Modjaz Miller Postdoc Fellow/UC Berkeley STScI, 04/30/2008. Fellow Stellar Death Detectives. Bob Kirshner (Former Advisor, Harvard University) - PowerPoint PPT PresentationTRANSCRIPT
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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
Mary
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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