Selection Effects on the Observed Redshift Dependence of Gamma-Ray Burst Jet Opening Angles

Lu, Rui-Jing; Wei, Junjie; Qin, Shu-Fu; Liang, En‐Wei

doi:10.1088/0004-637x/745/2/168

Cited by 41 publications

(39 citation statements)

References 111 publications

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“…The ratio between the mean jet energies for events produced at z = 7 and z = 1 is about 20, indicating a moderate evolution in the energy distribution. For this model, the derived local formation is R grb = 290 Gpc −3 yr −1 and the expected average jet energy is 3.0 × 10 49 erg, in agreement with the value derived by Lu et al (2012). Nevertheless, these authors have considered the opening angle to be related to the redshift, while in our simulations both quantities were statistically independent.…”

Section: Resultssupporting

confidence: 89%

Revisiting the formation rate and redshift distribution of long gamma-ray bursts

Kanaan

Pacheco

2013

A&A

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Using a novel approach, the distribution of fluences of long gamma-ray bursts derived from the Swift-BAT catalog was reproduced by a jet-model characterized by the distribution of the total radiated energy in γ-rays and the distribution of the aperture angle of the emission cone. The best fit between simulated and observed fluence distributions permits one to estimate the parameters of the model. An evolution of the median energy of the bursts is required to adequately reproduce the observed redshift distribution of the events when the formation rate of γ-ray bursts follows the cosmic star formation rate. For our preferred model, the median jet energy evolves as E J ∝ e 0.5(1+z) and the mean expected jet energy is 3.0 × 10 49 erg, which agrees with the mean value derived from afterglow data. The estimated local formation rate is R grb = 290 Gpc −3 yr −1 , representing less than 9% of the local formation rate of type Ibc supernovae. This result also suggests that the progenitors of long gamma-ray bursts have masses ≥90 M when a Miller-Scalo initial mass function is assumed.

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Section: Resultssupporting

confidence: 89%

Revisiting the formation rate and redshift distribution of long gamma-ray bursts

Kanaan

Pacheco

2013

A&A

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“…Also, it was noticed that the LGRBR was flatter at higher redshifts than the CSFH and that LGRBs were typically found in low-mass, low-metallicity galaxies (see e.g., Le Floc'h et al 2003;Savaglio et al 2009;Svensson et al 2010;Mannucci et al 2011). The difference in the LGRBR and CSFH, suggested in previous papers, can be understood if cosmic metallicity thresholds, evolving LGRB luminosity distributions (e.g., the progenitor evolves with redshift; Virgili et al 2011), evolving stellar initial mass functions (Wang & Dai 2011) or sample selection effects (see e.g., Coward et al 2008;Lu et al 2012) are included.…”

Section: Introductionmentioning

confidence: 81%

The longγ-ray burst rate and the correlation with host galaxy properties

Elliott

Greiner

Khochfar

et al. 2012

A&A

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Context. To answer questions on the start and duration of the epoch of reionisation, periods of galaxy mergers and properties of other cosmological encounters, the cosmic star formation history,ρ * or CSFH, is of fundamental importance. Using the association of long-duration gamma-ray bursts (LGRBs) with the death of massive stars and their ultra-luminous nature (>10 52 erg s −1 ), the CSFH can be probed to higher redshifts than current conventional methods. Unfortunately, no consensus has been reached on the manner in which the LGRB rate,ρ grb or LGRBR, traces the CSFH, leaving many of the questions mentioned mostly unexplored by this method. Aims. Observations by the gamma-ray burst near-infrared detector (GROND) over the past 4 years have, for the first time, acquired highly complete LGRB samples. Driven by these completeness levels and new evidence of LGRBs also occurring in more massive and metal rich galaxies than previously thought, the possible biases of theρ grb -ρ * connection are investigated over a large range of galaxy properties. Methods. The CSFH is modelled using empirical fits to the galaxy mass function and galaxy star formation rates. Biasing the CSFH by means of metallicity cuts, mass range boundaries, and other unknown redshift dependencies of the formρ grb ∝ρ * (1 + z) δ , aρ grb is generated and compared to the highly complete GROND LGRB sample. Results. It is found that there is no strong preference for a metallicity cut or fixed galaxy mass boundaries and that there are no unknown redshift effects (δ = 0), in contrast to previous work which suggest values of Z/Z ∼ 0.1−0.3. From the best-fit models obtained, we predict that ∼1.2% of the LGRB burst sample exists above z = 6. Conclusions. The linear relationship betweenρ grb andρ * suggested by our results implies that redshift biases present in previous LGRB samples significantly affect the inferred dependencies of LGRBs on their host galaxy properties. Such biases can lead to, for example, an interpretation of metallicity limitations and evolving LGRB luminosity functions.

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“…Recently, Fong et al (2012) reported on the X-ray light curve of the short burst 111020A, which showed a break at 2 d, leading to an estimated Θ jet = 3-8 deg for an assumed z = 0.5-1.5 and n ∼ 0.01-0.1 cm −3 . Figure 16 shows the observed distribution of jet half-opening angles of long-bursts based on the compilation of Lu et al (2012) compared to the short-burst sample (a similar plot has been recently shown by Fong et al (2012). The latter contains the results summarized in Table 5, supplemented by GRBs 061006 (Θ jet ∼ 5 deg), 070714B (Θ jet 4 deg), and 071227 (Θ jet 4 deg) taken from the compilation of Fan & Wei (2011), but using η γ = 0.2 instead of 1.0 (i.e., multiplying their numbers by 0.8; Eq.…”

Section: Jet Half-opening Anglesmentioning

confidence: 99%

“…Some caution is necessary, however. First of all, when calculating the jet half-opening angles, Lu et al (2012) assumed n = 0.1 cm −3 and η γ = 0.2 throughout. Even though Θ jet is only modestly sensitive to changes in both parameters (see Eq.…”

Section: Jet Half-opening Anglesmentioning

confidence: 99%

Multi-color observations of short GRB afterglows: 20 events observed between 2007 and 2010

Guelbenzu

Klose

Greiner

et al. 2012

A&A

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We report on follow-up observations of 20 short-duration gamma-ray bursts (GRBs; T 90 < 2 s) performed in g r i z JHK s with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is one of the most comprehensive data sets on GRB afterglow observations of short bursts published so far. In three cases, GROND was on target within less than 10 min after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint underlying host galaxy. In addition, GROND was able to image the optical afterglow and follow the light curve evolution in five further cases: GRBs 090305, 090426, 090510, 090927, and 100117A. In all other cases, optical/near-infrared upper limits can be provided on the afterglow magnitudes. After shifting all light curves to a common redshift, we find that the optical luminosities of the six events with light curves group into two subsamples. GRBs 090426 and 090927 are situated in the regime occupied by long-duration events (collapsars), while the other four bursts occupy the parameter space typical for merger events, confirming that the short-burst population is contaminated by collapsar events. Three of the aforementioned six bursts with optical light curves show a break: GRBs 090426 and 090510 (Papers I and II) as well as GRB 090305. For GRB 090927, no break is seen in the optical/X-ray light curve until about 150 ks/600 ks after the burst. The GROND multi-color data support the view that this burst is related to a collapsar event. A decay slope of the optical afterglow of GRB 100117A could be measured. For all six GRBs a lower limit on the corresponding jet opening angle can be set. Using these data supplemented by about ten events taken from the literature, we compare the jet half-opening angles of long and short bursts. We find tentative evidence that short bursts have wider opening angles than long bursts. However, the statistics are still very poor.

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Selection Effects on the Observed Redshift Dependence of Gamma-Ray Burst Jet Opening Angles

Cited by 41 publications

References 111 publications

Revisiting the formation rate and redshift distribution of long gamma-ray bursts

Revisiting the formation rate and redshift distribution of long gamma-ray bursts

The longγ-ray burst rate and the correlation with host galaxy properties

Multi-color observations of short GRB afterglows: 20 events observed between 2007 and 2010

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