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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2684 results found.

  1. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  2. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  3. GRB 240214A/1H 0451-560: MAXI/GSC detection
  4. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  5. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  7. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  8. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 240101B: Swift-BAT refined analysis
  10. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  11. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  12. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  13. GRB 231117A: Keck spectroscopy of afterglow candidate
  14. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  15. GRB231115A: Liverpool Telescope imaging
  16. GRB 231115A: AGILE/MCAL upper limits
  17. GRB 231115A: significance of INTEGRAL localization alignment with M82
  18. GRB 231111A: TNG tentative redshift
  19. GRB231110A: WFST Observation and upper limits
  20. IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event
  22. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  23. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  24. GRB 230911C: ATCA detection of possible radio counterpart
  25. IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
  26. IceCube-231014A - IceCube observation of a high-energy neutrino candidate track-like event
  27. IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
  28. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  29. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  30. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  31. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  32. IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
  33. GRB 230911D: NuSTAR Detection of Prompt Emission
  34. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  35. GRB 230812B: Assy optical observations, possible SN rise
  36. GRB 230812B: SAO RAS observations, possible re-brightening
  37. GRB 230812B: SAO RAS optical observations
  38. GRB230816A: Possible host and GIT detection of optical counterpart
  39. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  40. GRB 230805B: SAO RAS optical observations
  41. GRB 230728A: NOT optical observations and possible host galaxy
  42. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  43. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  44. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  45. GRB 230723B: Optical afterglow candidate from CAHA
  46. GRB 230723B: Optical limit from CAHA
  47. Swift Trigger 1178410: possible GRB 230709A
  48. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  49. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 230628E - VLT spectroscopic observations
  52. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  53. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  54. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  55. AT2023lcr: Pan-STARRS & ATLAS Observations
  56. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  57. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  58. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  60. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  61. GRB 230512A: Kitab possible afterglow candidate
  62. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  63. GRB 230506C: TSHAO possible afterglow candidate
  64. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  65. GRB 230430A: A short GRB from a neutron star merger
  66. GRB 230420A: Lowell Discovery Telescope Optical Detection
  67. GRB 230420A: Swift-BAT refined analysis
  68. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  69. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  70. GRB 230328B: redshift lower limit estimating
  71. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  72. GRB 230307A: short mininum variability timescale compatible with a merger origin
  73. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  74. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  75. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  76. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  77. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  78. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  79. GRB 230307A: Possible optical afterglow
  80. Solar Orbiter STIX observation of GRB 230307A
  81. GRB 230307A: GECAM detection of an extremely bright burst
  82. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  83. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  84. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  85. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 230216A: Swift-BAT refined analysis
  87. GRB 230216A: AKO Upper Limit
  88. GRB 230216A: Zadko observatory - Gingin optical observations
  89. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  90. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  91. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  92. GRB 230204B: Swift-XRT afterglow detection
  93. GRB 230205A: OHP/T193 optical observations
  94. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  95. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  96. GRB 221216A: Swift-BAT refined analysis
  97. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  98. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  99. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  100. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event

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