Radial distribution of GRBs in hostgalaxies

D.I. Kosenko1,2, O.S. Bartunov1, S.I.Blinnikov2,1, K.A.Postnov1

lisett@xray.sai.msu.ru, oleg@sai.msu.su, blinn@sai.msu.su, pk@sai.msu.ru

1Sternberg Astronomical Institute, 119992 Moscow, Russia2Institute for Theoretical and Experimental Physics, 117218 Moscow, Russia

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 1/13

Objects

• Analyze radial distribution of GRBs in hostgalaxies.

• Compare it with distribution of other objects(SNe, XB, DM).

• Find the relatives

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 2/13

Previous studies• D.Yu. Tsvetkov, S.I. Blin-

nikov, N.N. Pavlyuk;Gamma-ray Bursts, Type Ib/c

Supernovae and Star-forming

Sites in Host Galaxies,astro-ph/0101362

GRB→

surf. brightness of spirals PKS = 68%

surf. brightness of ellipticals PKS = 40%

OB associations and HII regions PKS = 4%

supernovae of type Ib/c PKS = 9%

• J.S. Bloom, S.R. Kulka-rni, S.G. Djorgovski; The

Observed Offset Distribution

of Gamma-Ray Bursts from

Their Host Galaxies: A Ro-

bust Clue to the Nature of

the Progenitors, ApJ, 123,1111, (2002)

GRB→NS-NS and BH-NS PKS . 2 × 10−3

BH-He PKS = 45%

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 3/13

DATAGRBs J. S. Bloom et al; ApJ, 123, 1111, (2002) + 12 new

SNe D. Tsvetkov, N. Pavluk (http://virtual.sai.msu.ru/∼pavlyuk/distrib/radial.html)

XB H.-J. Grimm, M. Gilfanov, and R. Sunyaev; astro-ph/0109239

DM: Burkert A. Burkert; ApJ, 447, 25-28 (1995)

DM: NFW Navarro, J. F.; Frenk, C. S.; White, S. D. M.; ApJ, 490, 493 (1997)

The Data Samplerx = Rx/Rgalaxy; GRB: σr = σR/Rgalaxy

Rgalaxy — half light radii of hosts

NOTE:

GRBs are at z ∼ 1, where almost all galaxies are dwarf: Rgalaxy ' 1.5 kpc, while SNe

are in nearby galaxies, where Rgalaxy ' 15 kpc

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 4/13

DATAGRBs J. S. Bloom et al; ApJ, 123, 1111, (2002) + 12 new

SNe D. Tsvetkov, N. Pavluk (http://virtual.sai.msu.ru/∼pavlyuk/distrib/radial.html)

XB H.-J. Grimm, M. Gilfanov, and R. Sunyaev; astro-ph/0109239

DM: Burkert A. Burkert; ApJ, 447, 25-28 (1995)

DM: NFW Navarro, J. F.; Frenk, C. S.; White, S. D. M.; ApJ, 490, 493 (1997)

The Data Samplerx = Rx/Rgalaxy; GRB: σr = σR/Rgalaxy

Rgalaxy — half light radii of hostsNOTE:GRBs are at z ∼ 1, where almost all galaxies are dwarf: Rgalaxy ' 1.5 kpc, while SNeare in nearby galaxies, where Rgalaxy ' 15 kpc

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 4/13

GRB 010921 (z = 0.45)HST Detection of the Afterglow and Host Galaxy: J. S. Bloom, S. R. Kulkarni, F. A.

Harrison, T. J. Galama, P. A. Price, S. G. Djorgovski, D. W. Fox, E. Berger, and D. A. Frail

(Caltech-NRAO-CARA GRB Collaboration)

The 1 and 3-sigma uncertainty contours

of the OT position measured from the

Palomar discovery images is shown.

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 5/13

DM Density Profiles

Burkert’s DM: ρDM ∝ 1(r/rcore+1)(r/rcore)2+1)

Burkert (1995) rcore ' ropt = 15 kpc

NFW DM: ρDM ∝ 1r/rs (r/rs+1)2

Navarro et al (1997) rs = 30 kpc

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 6/13

Allowing for GRB localizationerrors

each sampleof observationri is replacedwith normalizeddensity distribu-tion of its error

=⇒

Example offset distribution functions (J. S. Bloomet al, 2002)

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 7/13

Surface Density Profiles:

−1.5 −0.5 0.5 1.0

23

45

67

89

log(R Rgalaxy)

log(

σ)

SNIbcGRB

−1.5 −0.5 0.5 1.0

23

45

67

89

log(R Rgalaxy)

log(

σ)SNIaGRB

−2.0 −1.0 0.0 1.0

23

45

67

89

log(R Rgalaxy)

log(

σ)

XBGRB

−2.0 −1.0 0.0 1.0

23

45

67

89

log(R Rgalaxy)

log(

σ)

DMbDMnGRB

rcore = 0.5 kpc

rs = 1 kpc

rcore = 0.05 kpc

rs = 0.1 kpc

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 8/13

Estimates of Means and Medi-ans

〈r〉 ± σ〈r〉 Med(r) ± σMed(r)

GRB 0.260 ± 0.046 0.164 ± 0.019

GRB weighted 0.026 ± 0.001 0.020 ± 0.001

SNIb/c 0.238 ± 0.017 0.175 ± 0.014

SNIa 0.321 ± 0.012 0.245 ± 0.029

LMXB and HMXB 0.543 ± 0.027 0.545 ± 0.006

Dark Matter

Burkert’s: rcore = 0.05 kpc 0.020 ± 0.001 0.011 ± 0.001

Burkert’s: rcore = 0.5 kpc 0.087 ± 0.007 0.030 ± 0.003

NFW: rs = 0.1 kpc 0.021 ± 0.001 0.010 ± 0.001

NFW: rs = 1.0 kpc 0.063 ± 0.004 0.017 ± 0.001

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 9/13

Quantile-Quantile PlotsPlot of the quantiles of thefirst data set against thequantiles of the second da-ta set.

Quantile — fractionof points below thegiven value.

The advantages:

• The sample sizes do not need to be equal.

• Can be tested: shifts in location, shifts in scale,changes in symmetry, and the presence of outliers.

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 10/13

QQplots for GRB-SNIbc pair

−2.0 −1.0 0.0 0.5

−2.

0−

1.0

0.0

0.5

SNIbc, log(r)

GR

B, l

og(r

)

−2.0 −1.0 0.0 0.5

−2.

0−

1.0

0.0

0.5

SNIbc, log(r)

GR

Bw

, log

(r)

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 11/13

QQplots for GRB-DM pairs

Burkert’s DM profile:rcore = 0.05 kpc rcore = 0.5 kpc

NFW DM profile:rs = 0.1 kpc rcore = 1 kpc

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMb, log(r)

GR

B, l

og(r

)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMb, log(r)

GR

B, l

og(r

)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMb, log(r)

GR

Bw

, log

(r)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMb, log(r)

GR

Bw

, log

(r)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMn, log(r)

GR

B, l

og(r

)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMn, log(r)

GR

B, l

og(r

)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMn, log(r)

GR

Bw

, log

(r)

−2.0 −1.0 0.0−2.

0−

1.0

0.0

DMn, log(r)

GR

Bw

, log

(r)

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 12/13

Discussion/Results

• Max agreement in means and medians for GRB(〈r〉 = 0.26 and Med(r) = 0.16) and SNIbc(〈r〉 = 0.24 and Med(r) = 0.18)

• DM tests: VERY small values for scaleparameters (good agreement with smoothedGRB distribution)

Neutrinos and Explosive Events in the Universe, Erice, 2-13 July 2004 – p. 13/13