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The SN-GRB Connection from the SN perspective

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)

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The SN-GRB Connection from the SN perspective

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  1. 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

  2. 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)

  3. Outline: SN-GRB Connection • Introduction & Relevance: Definition, Massive Star Deaths SN-GRB connection, Outstanding Question • 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

  4. Stripped-Envelope SN Broad lines large expansion v large KE (1052 erg) “Hypernova” SN Classification • Spectra: Thermonuclear SN Core-Collapse SN HeI

  5. DEATHS OF MASSIVE STARS • Progenitor Models of SN Ib and Ic 1)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

  6. 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)

  7. Long GRB Short GRB 2s 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: g~1-1000 - Highly collimated jets: ~5-10o

  8. Stanek et al. (2003), Matheson et al. (2003) [see also Review (Woosely & Bloom 2006)] SN-LGRB Connection • Spectroscopic ID: SN Ic-bl • 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) Nearby GRB: low-luminosity, more common (~10-103x) than cosmological GRBs (Cobb et al., Soderberg et al., Guetta & Della Valle 2006, etc)

  9. 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)

  10. 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? SN-GRB CONNECTION Soderberg et al (2006)

  11. RELEVANCE of SN Ib & SN Ic • Deaths of Massive stars • Constrain explosion energetics and element synthesis, progenitors and remnants • Connection of SNIc-bl to GRBs • What is the range of SN Ic & SN Ic-bl properties? • How aspherical are (normal) SN Ib/c explosions? • Potential contaminationof 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

  12. Outline: SN-GRB Connection • Introduction & Relevance • 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

  13. 1.5m 1.3m 1.2m 6.5m MMT 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)

  14. 1) Doubles world supply of well-observed SN Ib/c Representative Data t • Sample (> 10 epochs of Optical Photometry or Spectra): • 11 SN Ib/IIb • 10 SN Ic • 1 GRB-SN 2) Peculiar objects: 05bf, 06jc

  15. Photometry: 2004-2007

  16. Theory: Light curves Spectra Mejecta SN Ejecta: v(r)r 56Ni KE Flux Credit: S. Blondin t LC width ejecta KE-3 Line width ejecta KE1/2

  17. GRB-SN SN2006aj/GRB060218 • z = 0.0335, Weak GRB Afterglow • short rise time (10 days) 98bw Time- stretched 98bw Diversity in SN-GRBs !! Modjaz et al. 2006

  18. Modeling & Implications of GRB060218/SN2006aj Data from Pian et al (2006) Mazzali et al. (2006): Ek ~ 2 x 1051 erg, M ~ 25 M Low-z GRB(-SN): low-lum., larger q, more common (~10-103x) than cosmological GRBs (Cobb et al., Soderberg et al., Guetta & Della Valle, etc)

  19. SN Ib/IIb SN Ic SN Ic-bl MV(@peak) Analysis: a) Distribution of MV SN Ia (@ peak) 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 Richardson et al. (2006) & my sample

  20. Analysis: Luminosity & LC Modjaz et al. in prep 1)No Luminosity - LC shape relationship for SN Ic 2) GRB-SN & broad-lined SN Ic have similar spectra GRB-SN appear more luminous (~2 mag)

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

  22. Late-time Spectra (~10 SN Ib/c) Modjaz, Kirshner, & Challis (2008b)

  23. Gerardy et al. (2002) Maeda et al. (2008) Asphericities are common in SN Ib/c - Oxygen ring ejection in SNR E0102.2-7219 (Tuohy & Dopita 1983, Blair et al. 2000) Modjaz, Kirshner, & Challis (2008b)

  24. Outline: SN-GRB Connection • Introduction & Relevance: • Sample and Observations of SN Ib/c & GRB-SN 3) Environments of SN Ib/c and GRB-SN & the SN-GRB connection: Blue light (proxy for mass) Abundance 4) Future Prospects & Conclusion

  25. 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

  26. Environmental Clues Local SN Ic and GRB have similar locations compared to host galaxy light • Similar (large) progenitor masses • - Additional ingredient needed for GRB production Fruchter et al (2006) LGRB SN Ic SN Ic-bl Kelly, Kirshner, & Pahre (2008, submitted)

  27. GRB Host galaxies • Fruchter et al. (2006): • GRB hosts are less luminous & smaller than SN II hosts SN II (Non-SN Ia) LGRB

  28. Nearby GRBs not unbiased tracers of star formation 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)

  29. 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

  30. 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)

  31. LMC SMC Local abundances of GRB-SN and broad-lined SN Ic Local SDSS galaxies (Tremonti et al 2004) in KD02 scale Z-Offset not due to selection effects Importance of galaxy-impartial SN surveys, e.g., PanSTARRS! Modjaz et al (2008)

  32. Z-Offset independent of Z-Diagnostic (Kewley & Dopita 02) (McGaugh 91) (Pettini & Pagel, Te ) (McGaugh 91) (Pettini & Pagel, Te ) “cut-off metallicity”: 0.2- 0.6 Z Most favored: 0.3 Z SN w/o GRB SN w/ GRB KS-Test: 3% 4% 3% KS-Test: 3% 4% 3%

  33. Not comparing same element! Need NIR spectra for high-z GRBs to observe emission lines Metallicities Via Absorption @ higher Redshift Prochaska et al (2007):No low-Z preference of GRB-DLA vs. QSO-DLA

  34. 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

  35. SN Ic ? SN Ib ? Future Prospects Chemical abundances for all SN Ib & SN Ic @ the explosion sites • 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

  36. Bridging low & high redshift Savaglio et al. (2008, submitted)

  37. Metallicity Gal-Yam et al. (2006) Mprog (Msol) Heger et al (2003): Single non-rotating Stars MAPPING between SN-type & Progenitor • Attempts: a) Theoretical b) Observational

  38. Theoretical Modeling • Ken Nomoto & collaborators

  39. 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

  40. SN Ia vs. SN Ic At maximum light At two weeks past maximum Blondin & Tonry (2007)

  41. SN Ia vs. SN Ic At maximum light At two weeks past maximum Blondin & Tonry (2007)

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

  43. 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? Late-time Data: a) SN2005bf Blueshift: ~2000 km/s OI: double-peaked • Moxy> 0.1- 1.1 Msun • Assuming: • T~ 3000-4500 K • -ne ~106 - 108 cm-3

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