The Astrophysical Journal (Jan 2025)
The Nature of Optical Afterglows without Gamma-Ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling
- Maggie L. Li,
- Anna Y. Q. Ho,
- Geoffrey Ryan,
- Daniel A. Perley,
- Gavin P. Lamb,
- Nayana A.J.,
- Igor Andreoni,
- G. C. Anupama,
- Eric C. Bellm,
- Edo Berger,
- Joshua S. Bloom,
- Eric Burns,
- Ilaria Caiazzo,
- Poonam Chandra,
- Michael W. Coughlin,
- Kareem El-Badry,
- Matthew J. Graham,
- Mansi Kasliwal,
- Garrett K. Keating,
- S. R. Kulkarni,
- Harsh Kumar,
- Frank J. Masci,
- Richard A. Perley,
- Josiah Purdum,
- Ramprasad Rao,
- Antonio C. Rodriguez,
- Ben Rusholme,
- Nikhil Sarin,
- Jesper Sollerman,
- Gokul P. Srinivasaragavan,
- Vishwajeet Swain,
- Zachary Vanderbosch
Affiliations
- Maggie L. Li
- ORCiD
- Department of Astronomy, Cornell University , Ithaca, NY 14853, USA ; [email protected]; Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Anna Y. Q. Ho
- ORCiD
- Department of Astronomy, Cornell University , Ithaca, NY 14853, USA ; [email protected]
- Geoffrey Ryan
- ORCiD
- Perimeter Institute for Theoretical Physics , Waterloo, Ontario N2L 2Y5, Canada
- Daniel A. Perley
- ORCiD
- Astrophysics Research Institute, Liverpool John Moores University , IC 2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
- Gavin P. Lamb
- ORCiD
- Astrophysics Research Institute, Liverpool John Moores University , IC 2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
- Nayana A.J.
- ORCiD
- National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus , Ganeshkhind Pune 411007, India
- Igor Andreoni
- ORCiD
- Joint Space-Science Institute, University of Maryland , College Park, MD 20742, USA; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Astrophysics Science Division , NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA; University of North Carolina at Chapel Hill , 120 E. Cameron Avenue, Chapel Hill, NC 27514, USA
- G. C. Anupama
- ORCiD
- Indian Institute of Astrophysics , II Block Koramangala, Bengaluru 560034, India
- Eric C. Bellm
- ORCiD
- DIRAC Institute, Department of Astronomy, University of Washington , 3910 15th Avenue NE, Seattle, WA 98195, USA
- Edo Berger
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138-1516, USA
- Joshua S. Bloom
- ORCiD
- Department of Astronomy, University of California , Berkeley, CA 94720, USA; Physics Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS 50B-4206, Berkeley, CA 94720, USA
- Eric Burns
- ORCiD
- Department of Physics & Astronomy, Louisiana State University , Baton Rouge, LA 70803, USA
- Ilaria Caiazzo
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Poonam Chandra
- ORCiD
- National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USA
- Michael W. Coughlin
- ORCiD
- School of Physics and Astronomy, University of Minnesota , Minneapolis, MN 55455, USA
- Kareem El-Badry
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Matthew J. Graham
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Mansi Kasliwal
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Garrett K. Keating
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138-1516, USA
- S. R. Kulkarni
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Harsh Kumar
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138-1516, USA; Physics Department, Indian Institute of Technology Bombay , Powai, 400 076, India; The NSF AI Institute for Artificial Intelligence and Fundamental Interactions , USA
- Frank J. Masci
- ORCiD
- IPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- Richard A. Perley
- ORCiD
- National Radio Astronomy Observatory , PO Box 0, Socorro, NM 87801, USA
- Josiah Purdum
- ORCiD
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA
- Ramprasad Rao
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138-1516, USA
- Antonio C. Rodriguez
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Ben Rusholme
- ORCiD
- IPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- Nikhil Sarin
- ORCiD
- Nordita, Stockholm University and KTH Royal Institute of Technology , Hannes Alfvens vag 12, SE-106 91 Stockholm, Sweden; Oskar Klein Centre for Cosmoparticle Physics, Department of Physics, Stockholm University , AlbaNova, Stockholm SE-106 91, Sweden
- Jesper Sollerman
- ORCiD
- Oskar Klein Centre, Department of Astronomy, Stockholm University , AlbaNova, SE-10691 Stockholm, Sweden
- Gokul P. Srinivasaragavan
- ORCiD
- Joint Space-Science Institute, University of Maryland , College Park, MD 20742, USA; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Astrophysics Science Division , NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Vishwajeet Swain
- ORCiD
- Department of Physics, Indian Institute of Technology Bombay , Powai, 400 076, India
- Zachary Vanderbosch
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
- DOI
- https://doi.org/10.3847/1538-4357/adc800
- Journal volume & issue
-
Vol. 985,
no. 1
p. 124
Abstract
In the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs). We present the identification, observations, and multiwavelength modeling of a recent such afterglow (AT 2023lcr), and model three literature events (AT 2020blt, AT 2021any, and AT 2021lfa) in a consistent fashion. For each event, we consider the following possibilities as to why a GRB was not observed: (1) the jet was off-axis; (2) the jet had a low initial Lorentz factor; and (3) the afterglow was the result of an on-axis classical GRB (on-axis jet with physical parameters typical of the GRB population), but the emission was undetected by gamma-ray satellites. We estimate all physical parameters using afterglowpy and Markov Chain Monte Carlo methods from emcee . We find that AT 2023lcr, AT 2020blt, and AT 2021any are consistent with on-axis classical GRBs, and AT 2021lfa is consistent with both on-axis low Lorentz factor (Γ _0 ≈ 5–13) and off-axis ( θ _obs = 2 θ _jet ) high Lorentz factor (Γ _0 ≈ 100) jets.
Keywords
- Gamma-ray bursts
- Transient sources
- Surveys
- Sky surveys
- Radio transient sources
- X-ray transient sources
