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"

43001 results found.

  1. GRB 251116C: SVOM/ECLAIRs refined analysis
  2. GRB 251116B: SVOM/ECLAIRs refined analysis
  3. GRB 251117A: AstroSat CZTI detection
  4. GRB 251114B: Insight-HXMT/HE detection
  5. GRB 251114B: GECAM-B detection of a short burst
  6. GRB 251117A: Fermi GBM observation
  7. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  8. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  9. GRB 251116D: Insight-HXMT/HE detection
  10. GRB 251115A: Swift-XRT observations
  11. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  12. GRB 251117A: SVOM/GRM observation of a short burst
  13. GRB 251117A: Tiled Swift observations
  14. GRB 251117A: Fermi-LAT detection
  15. LAT GRB251117.51: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  17. GRB 251116C: Swift/BAT arcminute localization of a burst
  18. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  19. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  20. GRB 251116B: SVOM/VT optical upper limit
  21. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  22. GRB 251116C: Swift-XRT observations
  23. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  24. GRB 251117A: Fermi GBM Final Localization Correction
  25. GRB 251116D: Glowbug gamma-ray detection
  26. EP251023a: Assy AZT-20 optical observations
  27. EP251023a: UAFO and AbAO optical observations
  28. GRB 251116D: AstroSat CZTI detection
  29. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  30. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  31. GRB 251116C: SVOM/VT optical upper limit
  32. GRB 251025B: further Mondy optical observations
  33. GRB 251111A: Mondy optical upper limit
  34. GRB 251116B: EP-FXT follow-up observation
  35. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  37. GRB 251116B: LCO optical upper limits
  38. GRB 251116C: LCO optical upper limits
  39. SVOM GRB251116C: Global MASTER-Net observations report
  40. GRB 251116C: SVOM detection of a burst
  41. GRB 251116B: SVOM detection of a burst
  42. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 251116A: Fermi GBM Final Real-time Localization
  44. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  45. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  46. GRB 251115A: Tiled Swift observations
  47. GRB 251115A: Fermi-LAT detection
  48. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  49. Fermi GRB 251115A: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
  51. GRB 251115A: Fermi GBM Final Real-time Localization
  52. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  53. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  54. GRB 251113A: Glowbug gamma-ray detection
  55. GRB 251113A: AstroSat CZTI detection
  56. GRB 251114B: Fermi GBM Final Real-time Localization
  57. GRB 251112A: Swift-BAT refined analysis
  58. Konus-Wind detection of GRB 251108C
  59. Fermi trigger No 784717756: Global MASTER-Net observations report
  60. Konus-Wind detection of GRB 251103A
  61. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  62. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  63. IPN triangulation of GRB 251108C
  64. The EP-WXT trigger 01709248221 is likely a flaring star
  65. Fermi GRB 251114A: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  67. GRB 251114A: Fermi GBM Final Real-time Localization
  68. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  69. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  70. Fermi GRB 251113A: Global MASTER-Net observations report
  71. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  72. GRB 251113A: Fermi GBM Final Real-time Localization
  73. GRB 251111A: SVOM/ECLAIRs refined analysis
  74. GRB 251025B: SVOM/ECLAIRs refined analysis
  75. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  76. GRB 251112A: Swift/UVOT Upper Limits
  77. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  78. GRB 251112A: Swift-XRT refined Analysis
  79. GRB 251108C: AstroSat CZTI detection
  80. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  81. GRB 251112B: MAXI/GSC detection
  82. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  83. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  84. GRB 251108B: Glowbug gamma-ray detection
  85. Swift Trigger 1413695: a possible GRB 251112A
  86. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  87. Fermi trigger No 784621743: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  89. GRB251111A: 1.3m DFOT optical upper limit
  90. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  91. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  92. GRB 251111A: Swift-XRT afterglow detection
  93. GRB 251111A: SVOM/VT optical observations with X-band data
  94. SVOM GRB251111.42: Global MASTER-Net observations report
  95. GRB 251111A: Swift-XRT observations
  96. SVOM GRB251111.22: Global MASTER-Net observations report
  97. GRB 251111A: EP-FXT counterpart detection
  98. GRB 251013C: Chandra X-ray observations and jet break detection
  99. GRB 251111A: SVOM/VT optical observations with VHF data
  100. GRB 251111A: KAIT optical upper limit

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov