| 1. |
- Andreoni, Igor, et al.
(författare)
-
Target-of-opportunity Observations of Gravitational-wave Events with Vera C. Rubin Observatory
- 2022
-
Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 260:1
-
Tidskriftsartikel (refereegranskat)abstract
- The discovery of the electromagnetic counterpart to the binary neutron star (NS) merger GW170817 has opened the era of gravitational-wave multimessenger astronomy. Rapid identification of the optical/infrared kilonova enabled a precise localization of the source, which paved the way to deep multiwavelength follow-up and its myriad of related science results. Fully exploiting this new territory of exploration requires the acquisition of electromagnetic data from samples of NS mergers and other gravitational-wave sources. After GW170817, the frontier is now to map the diversity of kilonova properties and provide more stringent constraints on the Hubble constant, and enable new tests of fundamental physics. The Vera C. Rubin Observatory's Legacy Survey of Space and Time can play a key role in this field in the 2020s, when an improved network of gravitational-wave detectors is expected to reach a sensitivity that will enable the discovery of a high rate of merger events involving NSs (∼tens per year) out to distances of several hundred megaparsecs. We design comprehensive target-of-opportunity observing strategies for follow-up of gravitational-wave triggers that will make the Rubin Observatory the premier instrument for discovery and early characterization of NS and other compact-object mergers, and yet unknown classes of gravitational-wave events.
|
|
| 2. |
- Salafia, Om Sharan, et al.
(författare)
-
Multiwavelength View of the Close-by GRB 190829A Sheds Light on Gamma-Ray Burst Physics
- 2022
-
Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 931:2
-
Tidskriftsartikel (refereegranskat)abstract
- We monitored the position of the close-by (about 370 Mpc) gamma-ray burst GRB 190829A, which originated from a massive star collapse, through very long baseline interferometry (VLBI) observations with the European VLBI Network and the Very Long Baseline Array, carrying out a total of nine observations between 9 and 117 days after the gamma-ray burst at 5 and 15 GHz, with a typical resolution of a few milliarcseconds. From a state-of-the art analysis of these data, we obtained valuable limits on the source size and expansion rate. The limits are in agreement with the size evolution entailed by a detailed modeling of the multiwavelength light curves with a forward-plus-reverse shock model, which agrees with the observations across almost 18 orders of magnitude in frequency (including the HESS data at TeV photon energies) and more than 4 orders of magnitude in time. Thanks to the multiwavelength, high-cadence coverage of the afterglow, inherent degeneracies in the afterglow model are broken to a large extent, allowing us to capture some unique physical insights; we find a low prompt emission efficiency of less than or similar to 10(-3), a low fraction of relativistic electrons in the forward shock downstream chi ( e ) < 13% (90% credible level), and a rapid decay of the magnetic field in the reverse shock downstream after the shock crossing. While our model assumes an on-axis jet, our VLBI astrometry is not sufficiently tight as to exclude any off-axis viewing angle, but we can exclude the line of sight to have been more than similar to 2 degrees away from the border of the gamma-ray-producing region based on compactness arguments.
|
|
