New Views of Compact Object Mergers Via Short Gamma-Ray Bursts

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New Views of Compact Object Mergers Via Short
Gamma-Ray Bursts

• Derek B. Fox
• Astronomy Astrophysics
• Penn State University

New Views of the Universe  KICP December 11, 2005
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Four Afterglows 050509B Swift BATXRT 050709
HETE, Chandra, Ground, HST 050724 Swift
BATXRT, Ground, VLA, Chandra 050813 Swift
BATXRT
Nature - 6 Oct 2005
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Four Afterglows 050509B Swift BATXRT 050709
HETE, Chandra, Ground, HST 050724 Swift
BATXRT, Ground, VLA, Chandra 050813 Swift
BATXRT
051210 Swift BATXRT
Nature - 6 Oct 2005
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• Eichler, Livio, Piran Schramm 1991
• Well-known GW wave source
• Known GRB model, but
• Short bursts
• Featureless spectra
• R-process elements
• Associated neutrino burst

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Short Bursts as Compact Object Mergers
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Evidence for mergers

• Circumstantial
• Old stellar populations
• No associated supernovae
• Energetics
• 100x less than long burst / collapsar (but see
  050813)
• 1000x greater than the magnetar giant flare (27
  Dec 2004)
• Afterglow energy comparable
• Okay for NS-NS, NS-BH
• And possibly
• Offsets from host galaxies
• Very old population

GRB 050509B (HST)
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Evidence for mergers

• Circumstantial
• Old stellar populations
• No associated supernovae
• Energetics
• 100x less than long burst / collapsar (but see
  050813)
• 1000x greater than the magnetar giant flare (27
  Dec 2004)
• Afterglow energy comparable
• Okay for NS-NS, NS-BH
• And possibly
• Offsets from host galaxies
• Very old population

GRB 050509B (HST)
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GRB 050509B Keck/Subaru
Kulkarni et al. 2005
Error radius 9.3 arcsec
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GRB 050509B HST Imaging

• Host galaxy
• Giant elliptical (one of 2 cD galaxies in
  cluster)
• Member of z0.225 cluster
• L 1.5 L
• SFR lt 0.1 M? yr-1

GRB 050509B (HST)
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GRB 050509B Host Galaxy
z0.225
SFR lt 0.1 M? yr-1
Bloom et al. 2005
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GRB 050724 Radio, NIR, Chandra
Berger et al. 2005
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Red elliptical z0.258 L1.6 L SFRlt0.03 M? yr-1
Kulkarni Cameron
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GRB 050724 Gemini Spectra
z0.257
Berger et al. 2005
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GRB 050813 Host Cluster
Error circle is original XRT localization
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GRB 050813 Imaging

• Galaxies B and C are at z0.72 (Prochaska et
  al. 2005)
• BUT!
• Galaxy cluster in vicinity has z1.8 (Gladders
  et al., in prep.)
• One likely cluster member is found in XRT circle
• No spectra as yet

XRT
B
C
10
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GRB 051210 Host Cluster (?)

• During meeting!
• APM cluster at 8 distance (Berger Fox, GCN
  4316)
• z0.114 (Dalton et al. 1997)
• Optical/radio searches ongoing

Cluster
X-ray
BAT
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Evidence for mergers

• Circumstantial
• Old stellar populations
• No associated supernovae
• Energetics
• 100x less than long burst / collapsar (but see
  050813)
• 1000x greater than the magnetar giant flare (27
  Dec 2004)
• Afterglow energy comparable
• Okay for NS-NS, NS-BH
• And possibly
• Offsets from host galaxies
• Very old population

GRB 050509B (HST)
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GRB 050709 HST Movie
4 epochs 6-35 days F814W Exp6360 s
Blue dwarf irregular galaxy z0.16 L0.1 L SFR gt
0.2 M? yr-1
Fox et al. 2005
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No SN / 050709
Fox et al. 2005 Hjorth et al. 2005b
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Hjorth et al. 2005a (Ground)
No SN / 050509B
HST
Kulkarni et al. 2005 (HST) IAB gt 27.7 mag
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Evidence for mergers

• Circumstantial
• Old stellar populations
• No associated supernovae
• Energetics
• 100x less than long burst / collapsar (but see
  050813)
• 1000x greater than the magnetar giant flare (27
  Dec 2004)
• Afterglow energy comparable
• Okay for NS-NS, NS-BH
• And possibly
• Offsets from host galaxies
• Very old population

GRB 050509B (HST)
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Adapted from Fox et al. 2005
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Evidence for mergers

• Circumstantial
• Old stellar populations
• No associated supernovae
• Energetics
• 100x less than long burst / collapsar (but see
  050813)
• 1000x greater than the magnetar giant flare (27
  Dec 2004)
• Afterglow energy comparable
• Okay for NS-NS, NS-BH
• And possibly
• Offsets from host galaxies
• Very old population

GRB 050509B (HST)
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Merger alternatives

• Collapsar and All-Magnetar models are in trouble.
  What about
• Multiple source populations
• Generic product of BHDisk
• Magnetars present at some level
• GRB 050709 in a blue dwarf star-forming galaxy
• Varieties of compact-object merger
• NS-NS vs. NS-BH
• BH-BH (Blandford)
• New ideas
• Accretion-Induced collapse of NS to BH
  (MacFadyen, Ramirez-Ruiz Zhang 2005)
   accomodates 100-s long X-ray flares

MacFadyen et al. 2005
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From Bursts to Rates
Nakar, Gal-Yam Fox astro-ph/0511254 Guetta
Piran astro-ph/0511239
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Limiting distances for LIGO
K.Thorne / NSF Review
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Binary NS Lifetimes

• 8 relativistic pulsar binary systems
• 2 discovered since 2003
• PSR J0737-3039A _at_ 87 Myr
• PSR J19060746 _at_ 300 Myr
• Merger rate dominated by short-lived systems
• Lifetime distribution like ?1 (flat in
  log-space)

1/H0
Champion et al. 2004 PSR J19060746
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Binary NS Lifetimes

• Kalogera et al. 2004
• Minimal rate is 7 LIGO-I events kyr1
• Maximal rate is very sensitive to new discoveries
  (e.g. PSR J19060746)
• Estimated range
• 7 to 122 kyr1 (95 c.l.)
• Max. one event per 8 years for LIGO-I

Kalogera et al. 2004
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SHB Rates Lifetimes

• Start with
• Cosmic SFR(z)
• BATSE catalog of burst fluences
• Guesses at luminosity and lifetime distributions
• Add
• 1. SHB redshifts (Swift, HETE, IPN)
• 2. Or matched SHB redshifts luminosities at a
  fixed threshold (Swift)
• 3. Estimate of burst beaming

Guetta Piran 2005
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BATSE SHB Fluences
Guetta Piran 2005
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SHBs Old and New
Old error boxes 1 cluster (z0.09), one bright
galaxy (z0.14), and two empty error boxes
(zgt0.25)  Gal-Yam et al. 2005
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Jet Break / 050709
301 beaming
Fox et al. 2005 Hjorth et al. 2005b
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Progenitor lifetimes

• Begin with star-formation rate SFR(z)
• Single power-law luminosity function allows use
  of all redshifts
• Test various progenitor lifetime distributions
• ? 6 Gyr for narrow log-normal distributions
• Inconsistent with ?1 distribution (red line)

Nakar, Gal-Yam Fox 2005
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Progenitor lifetimes

• Begin with star-formation rate SFR(z)
• Single power-law luminosity function allows use
  of all redshifts
• Test various progenitor lifetime distributions
• ? 6 Gyr for narrow log-normal distributions
• Inconsistent with ?1 distribution (red line)

Guetta Piran 2005
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Lifetimes Luminosities
Nakar, Gal-Yam Fox 2005
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Lifetimes Luminosities
Nakar, Gal-Yam Fox 2005
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Lifetimes Luminosities
z0.72 -gt 1.8

z0.114
Nakar, Gal-Yam Fox 2005
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Lifetimes Luminosities
z0.72 -gt 1.8

z0.114
Nakar, Gal-Yam Fox 2005
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SHBs and LIGO

• Long progenitor lifetimes and a high local rate
• R 10 Gpc-3 yr-1 for NS-NS with no beaming and
  no extrapolation to lower fluxes
• R gt 300 Gpc-3 yr-1 with 301 beaming
• At limit of 1047 erg s-1 (Tanvir et al. 2005)
  R105 Gpc-3 yr-1
• Max. 3 LIGO-I events yr1 0.3 yr1 more likely
• Compare 0.0070.122 yr1 from pulsars
• NS-BH or BH-BH models result in even higher rates

GRB 050709
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New Views of Compact Object Mergers
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New Views of Compact Object Mergers

• Do compact object mergers produce a strong EM
  signal?
• What is the local rate?
• GW detection LIGO, Virgo
• r-process elements
• Where when are they happening?
• Host types host offsets
• Progenitor lifetimes systemic velocities
• Are the explosions beamed?
• Do they expel significant quantities of
  nucleon-rich ejecta?
• X-ray flaring
• SN-like signal

Nakar, Gal-Yam Fox 2005
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New Views of Compact Object Mergers

• Do compact object mergers produce a strong EM
  signal?
• What is the local rate?
• GW detection LIGO, Virgo
• r-process elements
• Where when are they happening?
• Host types host offsets
• Progenitor lifetimes systemic velocities
• Are the explosions beamed?
• Do they expel significant quantities of
  nucleon-rich ejecta?
• X-ray flaring
• SN-like signal

• ? Short bursts
• ? LIGO-I detections feasible
• ? Majority elliptical clusters
• ? ? gt 3 Gyr
• ? 1/fb 30
• ? Theory still young (Kulkarni 2005)

Nakar, Gal-Yam Fox 2005
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New Views of Compact Object Mergers

• Progress will require
• More Swift redshifts, host galaxies, host
  clusters
• More beaming constraints
• Evaluation of Swift BAT thresholds
• or
• LIGO-I Science Run 5  in progress

Nakar, Gal-Yam Fox 2005
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Collaborators

• Caltech-NRAO GRB Collaboration
• S.R. Kulkarni, S.B. Cenko, A.M. Soderberg, P.B.
  Cameron, A. Gal-Yam, E. Nakar, D.-S. Moon, M.M.
  Kasliwal, F.A. Harrison at Caltech
• D.A. Frail (NRAO), P.A. Price (UH IfA), T. Piran
  (Hebrew U.), B. Schmidt (ANU), B. Penprase
  (Pomona), H.-S. Park (LLNL)
• Carnegie Observatories
• E. Berger, M. Gladders, E. Persson
• Swift Team
• Penn State J. Racusin, D.N. Burrows, J. Nousek,
  P. Mészáros, L. Gou
• GSFC C. Markwardt, T. Sakamoto
• UCL A. Blustin, M. Page
• SHBs with HST
• P. Kumar (UT), A. Panaitescu (LANL), R. Chevalier
  (UVA), A. MacFadyen (IAS)

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Coauthors

• M. Roth, Carnegie
• D. J. Sand, Caltech
• S. Shectman, Carnegie
• M. Takada, Tohuku U.
• T. Totani, Kyoto U.
• W. T. Vestrand, LANL
• D. Watson, Copenhagen
• R. White, LANL
• P. Wozniak, LANL
• J. Wren, LANL

• B. L. Lee, U. Toronto
• P. J. McCarthy, Carnegie
• D. C. Murphy, Carnegie
• S. E. Persson, Carnegie
• B. A. Peterson, ANU
• M. M. Phillips, Carnegie
• J. Rich, ANU
• M. Rauch, Carnegie
• K. Roth, Gemini Obs

• K. Aoki, NAOJ
• L. L. Cowie, UH IfA
• A. Dey, NOAO
• S. Evans, LANL
• H. Furusawa, TIT
• K. C. Hurley, Berkeley
• N. Kawai, TIT
• G. Kosugi, NAOJ
• W. Krzeminski, Carnegie
• D. C. Leonard, Caltech

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The End