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The Optically Unbiased GRB Host (TOUGH) sample. TOUGH 1: Survey Design and Catalogues (Hjorth et al.). TOUGH 2: Fundamental Properties (Malesani et al.). TOUGH 3: Redshift Distribution (Jakobsson et al.). TOUGH 4: Ly α Emitters (Milvang-Jensen et al.). - PowerPoint PPT Presentation
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The Optically Unbiased GRB Host (TOUGH) sample
Palli JakobssonCentre for Astrophysics & Cosmology
University of Iceland
TOUGH 1: Survey Design and Catalogues (Hjorth et al.)
TOUGH 2: Fundamental Properties (Malesani et al.)
TOUGH 3: Redshift Distribution (Jakobsson et al.)
TOUGH 4: Lyα Emitters (Milvang-Jensen et al.)
TOUGH 5: Radio Survey at z < 1 (Michałowski et al.)
TOUGH 6: Host Luminosity Function (Schulze et al.)
Jens Hjorth (PI)Jóhán Fýnbó(Icelandic expert)
Bo Milvang-Jensen(Eurovision expert)
Daniele Malesani(GCN expert)
Bob Chapman(Dr. Who expert)
Nial Tanvir(world record expert)
The TOUGH Guys
Thomas Krühler(X-shooter expert)
69 Host Galaxies (R-band)
Redshift DistributionBefore TOUGH:
<z> = 2.39
Redshift DistributionBefore TOUGH:
<z> = 2.39
TOUGH (FORS):
<z> = 2.23
Redshift Distribution
TOUGH (FORS):
<z> = 2.23
Before TOUGH:<z> = 2.3915 new
redshifts
68/69 hosts have a redshift
constraint
TOUGH (X-shooter):<z> = 2.23
77% (53/69) redshift
completion
1. A Swift-detected GRB with t90 > 2 s.
2. XRT afterglow position distributed within 12 hours.
3. Small foreground Galactic extinction: AV < 0.5 mag.
4. Favorable declination: -70° < δ < 27°.
5. Afterglow error radius < 2”.
March 2005 – August 2007: 69 GRBs
75% had an optical/NIR afterglow
TOUGH Sample Selection Criteria
55% had a reported redshift (38/69)
Blue: short bursts
Empty circles: withoutan X-ray afterglow
Filled circles: withan X-ray afterglow
Crosses: untriggered bursts
Sample Selection: Sky Map
R-band detections:53/69 = 77%
K-band detections:24/60 = 40%
How Many Hosts Detected (R-band)?
-15 > MB > -22
GRB hosts aremostly subluminous
In line with previousfindings based onsmaller and less
complete samples
Host Properties
Blue colours:<R – K> ~ 3
Blue: with OA
Red: no OA
Only 1/56 ERO
Host Properties
Tanvir et al. (2008)Jaunsen et al. (2008)Perley et al. (2009)
Levesque et al. (2010)Krühler et al. (2011)
Redshift Determination (R < 25 mag)
Redshift Determination(z = 0.84) (z =
1.92)
(z = 0.84)
Cumulative Redshift Distribution
KS: < 1%KS: 52%
SFR1(Li 2008 modified by
Langer & Norman 2006low-metallicity
correction)
SFR2(Model A from Schmidt 2009)
SFR Density Histories
Lyα and the Role of Dust