1. 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

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
1) Introduction & Relevance:
- Key Question: Production conditions for SN-GRB? SN Ic with and without GRBs
2) Sample and Observations of SN Ib/c & SN-GRB:
- Are only SN-GRBs aspherical ? Probably NO
3) Environments of SN Ib/c and GRB-SN:
- Higher Progenitor Mass for SN-GRB? Probably NO
- Low Metallicity for SN-GRB? Probably YES!
4) Conclusion & Future Prospects

4. 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

5. What is a Supernova?
Just Google it:

6. What is a Supernova, really?
What is a Supernova (SN), really?
What is a Supernova, really?
Brilliant Explosion of a star
SN 1994D (Credit: P. Challis)
SN 1994D (Credit: P. Challis)

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

8. 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

9. 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)

10. Massive Stellar Evolution
Janka et al. (2005): 3D simulations, follow explosion
Woosley, Heger & Weaver (2002)
Woosley: Star undergoes successive stages of fusion in the core [H, He, C, Ne. Oxy, Si] & shells all hydrostatic burning phases - > e capture & photo-disintrigation
Janka: Explosion only (neutrino-driven),15 M_sun, assuming initial model of spherical symmetry and non-rotating. Accretion onto nascent NS: bipolar nature. Blue: SN shockwave, Red: Accretion, Grey: Neutrino-heated, hot ejecta
Nucleosynthesis: massive stars; also r-process synthesis possible before explosion
for low-Z & massive stars (PopIII): alpha-rich elements

11. Gamma-Ray Bursts: Extreme Explosions
Short GRB
Long GRB 2s
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

12. 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= (Malesani et al.2004)
4) XRF020903
z=0.25 (Soderberg et al. 2005, Bersier et al. 2006)
5) GRB060218/SN06aj
z = , 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)]
98bw: E_iso = 10^47-10^48 erg
Nearby GRB: low-luminosity, more common (~10-103x) than cosmological GRBs (Cobb et al., Soderberg et al., Guetta & Della Valle 2006, etc)

13. 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~ erg
Image: SN shock visible as blue:
The passage of the jet initiates a shock that propagates to lower latitudes and eventually exploded the whole star
Initial SN shock seen in pale blue at R=2x10^10cm
SMALL PICTURE: Jet after 8sec; center of 15 WR star, Lorenzfactor ~200
For initial collimation of 10 deg
MacFadyen, Woosley & Heger (2001)

14. SN-GRB CONNECTION What fraction? What distinguishes SN with GRB from
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?
RATES:
Soderberg et al (2006)

15. 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 (pre-CCD SNe)
NEXT STEP: homogeneous & densely covered data set

16. Outline: SN-GRB Connection
Introduction & Relevance
Sample and Observations of SN Ib/c & GRB-SN:
SN - Sample ( )
Analysis: E.g. Are SN round?
3) Environments of SN Ib/c and GRB-SN & the SN-GRB connection
4) Future Prospects & Conclusion

17. 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

18. IR Light Curves
Yoshii et al 2004
PAIRITEL: automated, ex-2MASS, 1.3 m telescope, dedicated IR facility (Bloom, Szentgyorgyi, et al)
Well-understood 2MASS camera and characteristics, photometric calibration via 2MASS
Few NIR LCs for SN Ib/c
(e.g., SN 2004aw: Taubenberger et al. 2006)

19. 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/c
2) Peculiar objects: 05bf, 06jc

20. Photometry:

21. 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

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

23. 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)

24. Analysis: a) Distribution of MV
SN Ia peak)
SN Ib/IIb
SN Ic
SN Ic-bl
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

25. 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)

26. Late-time Line Diagnostics
- GRB
SN 2003jd (SN Ic-bl) :
Off-axis GRB? (Mazzali et al. 2005)
Probe deeper into SN ejecta
than early-time spectra:
1) Line Ratios: state of core before explosion
(Foley et al , 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)

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

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

29. 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

30. 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

31. Environmental Clues Fruchter et al (2006)
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)

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

33. Host galaxies of LGRBs Low-metallicity, subluminous host galaxies:
Nearby GRBs not unbiased tracers of star formation
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 )
high-z
(Le Floc’h et al 2003, Fruchter et al. 2006)
Stanek, .., Modjaz et al (2007)

34. Stellar Evolution @ low Z
Progenitor Stars of GRB:
Rotating massive 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

35. 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)

36. Local abundances of GRB-SN and broad-lined SN Ic
Local SDSS galaxies (Tremonti et al 2004) in KD02 scale
SMC
LMC
SDSS: z< 0.2, oxy~8.6 = 0.5 Z if Z_sol = 8.9
0.3 dex = FACTOR of 2
0.5 dex = FACTOR of 3
0.7 dex = FACTOR of 5
Z-Offset not due to selection effects
Importance of galaxy-impartial SN surveys, e.g.,
PanSTARRS!
Modjaz et al (2008)

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

38. Do GRB host galaxies follow L-Z?
No at low z
Savaglio et al (2006) (GHostS conference proceeding)
GRB hosts 0.4 < z < 1
Probably No at higher z
Kewley et al. (2007)
Brown et al. (2008)
Savaglio:

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

40. “Long (?)” GRBs without SN
Or: like Long GRB?
(Thoene et al. 2008)
GRB060605: Short GRB-like
(Levesque & Kewley 2007)
GRB060614
(Gal-Yam et al, Fynbo et al, Della Valle et al, 2006)
GRB060614
GRB060605
(Fynbo et al. 2006)
But really Long GRBs? GRB Identity Crisis!
Environmental studies might help!

41. 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
4) Future Prospects & Conclusion

42. 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

43. Future Prospects
Chemical abundances for all SN Ib & SN 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
SN Ic ?
SN Ib ?

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

45. Massive Star Evolution
Conti Scenario (Maeder & Conti 1994, Massey 2003)
~ 8>M>20 Mo : OB RSG BSG SN
~20>M>25 Mo : O RSG WN SN
~25>M>40 Mo : O RSG WN WC SN
~40>M>85 Mo : O WN WC SN
M>85 Mo : O LBV WN WC SN
(for Galactic metallicity)
WN: no/little H, strong He, N Wolf-Rayet Stars
WC: no N, strong C, O, some He
Mass Loss: During MS & WR stage
Nature of Mass Loss?

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

47. Theoretical Modeling
Ken Nomoto & collaborators

48. LC of 2003dh

49. IR Photometry: 1) Precision
E.g., SN 2005hg (Ib)
2MASS stars SN

50. “Maverick”: SN 2005bf (Ib-pec)
Tominaga et al (2005)
See also Folatelli et al. (2006)
Days after UT March

51. “Maverick”: SN 2005bf (Ib-pec)
M. Modjaz
Tominaga et al (2005):
56Ni ~ 0.3 Msun Mej~6-7 Msun , Mprog~25-30 Msun, NS remnant
He lines

52. SN2006jc (Ib-n)
Days after B max
See also Foley et al. (2007), Pastorello et al. (2007), Smith et al. (astro-ph)
NIR Excess -> Dust emission

53. Importance of NIR contribution
F (NIR)/F(bol)
SN 2005bf
J. Deng, M. Modjaz

54. IR photometry
Elias et al. (1986),Yoshii et al (2004)

55. Enigmatic GRB/XRF
Campana et al 2006
Campana et al 2006

56. GRB in Radio & Xray
Soderberg et al 2006

57. 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 & available at

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

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

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

61. b) cont’d: Include “all SN-GRB” ?
-1 mag --
1.9 mag =
Ferrero et al 2006

62. Late-time Data: a) SN2005bf
Blueshift: ~2000 km/s
OI: double-peaked
Moxy> Msun
Assuming:
T~ K
-ne ~ cm-3
H: not blue-shifted, FWHM = 9000 km/s
Msun for thick shell (if v = v)
at R=2x1016 cm
Predicted: LX~4 x 1039 erg s-1
From WR Wind?

63. SN2006aj/GRB060218
Kocevski et al (2007)
Modjaz (2007)