‘Orphan’ afterglows in the Universal structured jet model for γ-ray bursts

Rossi, Elena M.; Perna, Rosalba; Daigne, F.

doi:10.1111/j.1365-2966.2008.13736.x

Cited by 31 publications

(34 citation statements)

References 49 publications

(63 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nondetections of OA are in agreement with current theoretical predictions (Totani & Panaitescu 2002;Nakar et al 2002;Zou et al 2007;Rossi et al 2008;Metzger et al 2015). However, these works either extrapolated the properties of a few known GRB afterglows to the orphans (e.g., Totani & Panaitescu 2002) or assumed basic prescriptions for the known GRB population properties or for the afterglow emission model.…”

Section: Introductionsupporting

confidence: 80%

“…However, also in this scenario OAs could still be present if either the prompt emission at large angles is below any detector threshold or if the jet is uniform within a relatively narrow core and highly structured (i.e., with a steeply decreasing energy profile) outside it, as suggested by recent results from the modeling of the luminosity function . In this model, the detection rates of OA would, at any rate, be lower than in the top-hat model adopted here as shown in Rossi et al (2008).…”

Section: Discussionmentioning

confidence: 98%

“…So far, we considered the radio band predicting that the Square Kilometer Array (SKA), reaching the μJy flux limit, could see up to ∼0.2-1.5 OA deg −2 yr −1 (Ghirlanda et al 2014). Alternatively, the nondetection of OA could be due to the structure of the jet (Rossi et al 2008;Salafia et al 2015).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Unveiling the population of orphanγ-ray bursts

Ghirlanda

Salvaterra

Campana

et al. 2015

A&A

View full text Add to dashboard Cite

Gamma-ray bursts (GRBs) are detectable in the γ-ray band if their jets are oriented toward the observer. However, for each GRB with a typical θ jet , there should be ∼2/θ 2 jet bursts whose emission cone is oriented elsewhere in space. These off-axis bursts can eventually be detected when, due to the deceleration of their relativistic jets, the beaming angle becomes comparable to the viewing angle. Orphan afterglows (OAs) should outnumber the current population of bursts detected in the γ-ray band even if they have not been conclusively observed so far at any frequency. We compute the expected flux of the population of orphan afterglows in the mm, optical, and X-ray bands through a population synthesis code of GRBs and the standard afterglow emission model. We estimate the detection rate of OAs with ongoing and forthcoming surveys. The average duration of OAs as transients above a given limiting flux is derived and described with analytical expressions: in general OAs should appear as daily transients in optical surveys and as monthly/yearly transients in the mm/radio band. We find that ∼2 OA yr −1 could already be detected by Gaia and up to 20 OA yr −1 could be observed by the ZTF survey. A larger number of 50 OA yr −1 should be detected by LSST in the optical band. For the X-ray band, ∼26 OA yr −1 could be detected by the eROSITA. For the large population of OA detectable by LSST, the X-ray and optical follow up of the light curve (for the brightest cases) and/or the extensive follow up of their emission in the mm and radio band could be the key to disentangling their GRB nature from other extragalactic transients of comparable flux density.

show abstract

Section: Introductionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 98%

See 1 more Smart Citation

Unveiling the population of orphanγ-ray bursts

Ghirlanda

Salvaterra

Campana

et al. 2015

A&A

View full text Add to dashboard Cite

show abstract

“…Here we consider the standard model of a uniform jet for GRBs but the detection rate of OA has been explored (Rossi, Perna, & Daigne 2008) also for a universal structured jet model (Rossi, Lazzati, & Rees 2002;Zhang & Meszaros 2002).…”

Section: Ghirlanda Et Almentioning

confidence: 99%

GRB Orphan Afterglows in Present and Future Radio Transient Surveys

Ghirlanda

Burlon

Ghisellini

et al. 2014

Publ. Astron. Soc. Aust.

View full text Add to dashboard Cite

Orphan Afterglows (OA) are slow transients produced by Gamma Ray Bursts seen off-axis that become visible on timescales of days/years at optical/NIR and radio frequencies, when the prompt emission at high energies (X and γ rays) has already ceased. Given the typically estimated jet opening angle of GRBs θ jet ∼ 3 • , for each burst pointing to the Earth there should be a factor ∼ 700 more GRBs pointing in other directions. Despite this, no secure OAs have been detected so far. Through a population synthesis code we study the emission properties of the population of OA at radio frequencies. OAs reach their emission peak on year-timescales and they last for a comparable amount of time. The typical peak fluxes (which depend on the observing frequency) are of few μJy in the radio band with only a few OA reaching the mJy level. These values are consistent with the upper limits on the radio flux of SN Ib/c observed at late times. We find that the OA radio number count distribution has a typical slope −1.7 at high fluxes and a flatter (−0.4) slope at low fluxes with a break at a frequency-dependent flux. Our predictions of the OA rates are consistent with the (upper) limits of recent radio surveys and archive searches for radio transients. Future radio surveys like VAST/ASKAP at 1.4 GHz should detect ∼ 3 × 10 −3 OA deg −2 yr −1 , MeerKAT and EVLA at 8.4 GHz should see ∼ 3 × 10 −1 OA deg −2 yr −1 . The SKA, reaching the μJy flux limit, could see up to ∼ 0.2 − 1.5 OA deg −2 yr −1 . These rates also depend on the duration of the OA above a certain flux limit and we discuss this effect with respect to the survey cadence.

show abstract

“…As the GRB jet sweeps the interstellar medium, the Lorentz factor of the jet is decelerated and the jet starts to expand sideways, eventually 1 http://www.rssd.esa.int/GAIA/ becoming detectable by off-axis observers. These afterglows are not associated with the prompt GRB emission and are called orphan afterglows (OA) (Nakar et al 2002;Rossi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Searching for the first stars with theGaiamission

Krone-Martins¹,

Ishida²,

Ciardi³

2012

A&A

View full text Add to dashboard Cite

Aims. We construct a theoretical model to predict the number of orphan afterglows (OA) from gamma-ray bursts (GRBs) triggered by primordial metal-free (Pop III) stars expected to be observed by the Gaia mission. In particular, we consider primordial metal-free stars that were affected by radiation from other stars (Pop III.2) as a possible target. Methods. We use a semi-analytical approach that includes all relevant feedback effects to construct cosmic star formation history and its connection with the cumulative number of GRBs. The OA events are generated using the Monte Carlo method, and realistic simulations of Gaia's scanning law are performed to derive the observation probability expectation. Results. We show that Gaia can observe up to 2.28 ± 0.88 off-axis afterglows and 2.78 ± 1.41 on-axis during the five-year nominal mission. This implies that a nonnegligible percentage of afterglows that may be observed by Gaia (∼10%) could have Pop III stars as progenitors.

show abstract

‘Orphan’ afterglows in the Universal structured jet model for γ-ray bursts

Cited by 31 publications

References 49 publications

Unveiling the population of orphanγ-ray bursts

Unveiling the population of orphanγ-ray bursts

GRB Orphan Afterglows in Present and Future Radio Transient Surveys

Searching for the first stars with theGaiamission

Contact Info

Product

Resources

About