Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28237 results found.

  1. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  2. GRB 250818B: SAO RAS optical observations
  3. GRB 250818A: Swift-XRT refined Analysis
  4. GRB 250818B: EP-FXT counterpart detection
  5. GRB 250818A: Swift-BAT refined analysis
  6. GRB 250818B: KAIT optical observations
  7. GRB 250818A: Swift/UVOT Upper Limits
  8. LIGO/Virgo/KAGRA S250818t: Updated Sky localization
  9. GRB 250818A: Enhanced Swift-XRT position
  10. GRB 250813B: SVOM/ECLAIRs refined analysis
  11. GRB 250818A: Fermi GBM Observation
  12. LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations
  13. GRB 250814A: Further GRAWITA TNG NIR observations
  14. GRB 250818B: Swift-XRT afterglow detection
  15. GRB 250818B: SVOM detection of a short burst
  16. LIGO/Virgo/KAGRA S250818t: Identification of a GW compact binary merger candidate
  17. GRB 250818A: Swift detection of a burst
  18. sb25081602: Swift-XRT observations
  19. GRB 250816A: SVOM/GRM observation of a short burst
  20. GRB 250814A: Swift-BAT refined analysis
  21. GRB 250813B: Liverpool Telescope optical upper limits
  22. GRB 250814A: Further COLIBRÍ optical upper limit
  23. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  24. GRB 250814A: GRAWITA TNG NIR observations
  25. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  26. GRB 250813B: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  27. GRB250814A: TRT optical upper limits
  28. GRB 250814B: SVOM/GRM observation
  29. LIGO/Virgo/KAGRA S250813k: Swift XRT observations, 2 X-ray sources
  30. GRB 250813B: SVOM/GRM observation
  31. GRB 250814A: P200/WIRC observations of the afterglow candidate
  32. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  33. GRB 250814A: KAIT optical upper limit
  34. GRB 250814A: Swift-XRT refined Analysis
  35. GRB 240814A: Fermi GBM Observation
  36. GRB 250814A: Possible afterglow candidate from P200/WIRC
  37. GRB 250813B: Fermi GBM Observation
  38. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  39. GRB 250814A: J-band upper limit from WINTER
  40. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  41. GRB 250813B: NOT observations of the optical afterglow
  42. GRB 250814A: COLIBRÍ optical upper limit
  43. GRB 250813A: AstroSat CZTI detection
  44. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  45. GRB 250814A: DDOTI Optical Upper Limit
  46. GRB 250813B: EP-FXT counterpart detection
  47. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  48. GRB 250813B: Swift-XRT afterglow detection
  49. GRB 250814A: Swift detection of a burst coincident with a subthreshold GW trigger
  50. GRB 250813B: SVOM/COLIBRÍ (FM-GFT) optical observations
  51. GRB 250813B: SVOM detection of a bright long burst (Correction for GCN 41352).
  52. GRB 250813B: SVOM detection of a bright long burst
  53. LIGO/Virgo/KAGRA S250813k: NED Galaxies in the 4-Update Localization Volume
  54. LIGO/Virgo/KAGRA S250813k: Updated Sky localization
  55. EP250812a: Nickel optical upper limit
  56. GRB 250812A: VLT X-shooter spectroscopic redshift confirmation z = 2.571
  57. EP250812a: NOT, NTT, and GS observations
  58. GRB 250812A: Swift/UVOT Detection
  59. EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
  60. EP250812a: Liverpool Telescope upper limits
  61. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  62. LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
  63. GRB 250812A: EP-FXT counterpart detection
  64. GRB 250807B: Swift-BAT refined analysis
  65. EP 250812a: GOTO optical upper limit
  66. GRB 250812A: Kilonova-Catcher optical afterglow detection
  67. EP250812a: Swift-XRT counterpart detection
  68. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  69. EP250812a: Einstein Probe detection of an X-ray transient
  70. GRB 250812A: Swift-XRT afterglow detection
  71. GRB 250812A: TRT likely optical counterpart detection
  72. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  73. GRB 250809A: Swift-BAT refined analysis
  74. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  75. GRB 250807A: Swift-BAT refined analysis
  76. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  77. GRB 250809A: Swift/UVOT Detection
  78. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  79. Corrected Swift-XRT Refined Analysis of GRB 250809A
  80. GRB 250809A: Swift-XRT refined Analysis
  81. GRB 250809A: LCOGT Optical Upper Limits
  82. GRB 250808A: VLT X-shooter candidate counterpart
  83. GRB 250809A: Swift detection of a gamma ray burst
  84. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  85. GRB 250808A: Fermi GBM Observation
  86. GRB 250808A: Swift-XRT candidate counterpart detection
  87. GRB 250807B: Swift/UVOT Detection
  88. GRB 250807B: Kilonova-Catcher optical afterglow detection
  89. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 250807A: Swift/UVOT Detection
  91. GRB 250807A: Swift-XRT refined Analysis
  92. GRB 250806A: SVOM/MXT refined analysis
  93. EP250807a: NTT z-band optical upper limit
  94. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  95. GRB 250807A: SVOM/GRM observation
  96. GRB 250807A: AstroSat CZTI detection of bright long burst
  97. GRB 250807B: Swift-XRT refined Analysis
  98. EP250807a: EP-WXT detection of a fast X-ray transient
  99. EP 250807.979: GOTO optical upper limit
  100. EP250807a: COLIBRÍ optical upper limit

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov