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"

39265 results found.

  1. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  2. GRB 251116D: SVOM/GRM observation of a long GRB
  3. GRB 251119A: SVOM detection of a possible burst
  4. EP251118a: NOT spectroscopic redshift of z = 1.216
  5. EP251118a: Global MASTER-Net observations report
  6. LAT GRB251118.86: Global MASTER-Net observations report
  7. GRB 251118A: Fermi-LAT detection
  8. GRB 251118A: Swift ToO observations
  9. Fermi GRB 251118B: Global MASTER-Net observations report
  10. GRB 251118B: Fermi GBM Final Real-time Localization
  11. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  12. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  13. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  14. GRB 251118A: Fermi GBM Final Real-time Localization
  15. GRB 251116C: SVOM/ECLAIRs refined analysis
  16. GRB 251116B: SVOM/ECLAIRs refined analysis
  17. GRB 251117A: AstroSat CZTI detection
  18. GRB 251114B: Insight-HXMT/HE detection
  19. GRB 251114B: GECAM-B detection of a short burst
  20. GRB 251117A: Fermi GBM observation
  21. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  22. GRB 251116D: Insight-HXMT/HE detection
  23. GRB 251115A: Swift-XRT observations
  24. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  25. GRB 251117A: SVOM/GRM observation of a short burst
  26. GRB 251117A: Tiled Swift observations
  27. GRB 251117A: Fermi-LAT detection
  28. LAT GRB251117.51: Global MASTER-Net observations report
  29. GRB 251116C: Swift/BAT arcminute localization of a burst
  30. GRB 251116B: SVOM/VT optical upper limit
  31. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  32. GRB 251116C: Swift-XRT observations
  33. GRB 251117A: Fermi GBM Final Localization Correction
  34. GRB 251116D: Glowbug gamma-ray detection
  35. EP251023a: Assy AZT-20 optical observations
  36. EP251023a: UAFO and AbAO optical observations
  37. GRB 251116D: AstroSat CZTI detection
  38. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  39. GRB 251116C: SVOM/VT optical upper limit
  40. GRB 251025B: further Mondy optical observations
  41. GRB 251111A: Mondy optical upper limit
  42. GRB 251116B: EP-FXT follow-up observation
  43. GRB 251116B: LCO optical upper limits
  44. GRB 251116C: LCO optical upper limits
  45. SVOM GRB251116C: Global MASTER-Net observations report
  46. GRB 251116C: SVOM detection of a burst
  47. GRB 251116B: SVOM detection of a burst
  48. GRB 251116A: Fermi GBM Final Real-time Localization
  49. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  50. GRB 251115A: Tiled Swift observations
  51. GRB 251115A: Fermi-LAT detection
  52. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  53. Fermi GRB 251115A: Global MASTER-Net observations report
  54. GRB 251115A: Fermi GBM Final Real-time Localization
  55. GRB 251113A: Glowbug gamma-ray detection
  56. GRB 251113A: AstroSat CZTI detection
  57. GRB 251114B: Fermi GBM Final Real-time Localization
  58. GRB 251112A: Swift-BAT refined analysis
  59. Konus-Wind detection of GRB 251108C
  60. Fermi trigger No 784717756: Global MASTER-Net observations report
  61. Konus-Wind detection of GRB 251103A
  62. IPN triangulation of GRB 251108C
  63. Fermi GRB 251114A: Global MASTER-Net observations report
  64. GRB 251114A: Fermi GBM Final Real-time Localization
  65. Fermi GRB 251113A: Global MASTER-Net observations report
  66. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  67. GRB 251113A: Fermi GBM Final Real-time Localization
  68. GRB 251111A: SVOM/ECLAIRs refined analysis
  69. GRB 251025B: SVOM/ECLAIRs refined analysis
  70. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  71. GRB 251112A: Swift/UVOT Upper Limits
  72. GRB 251112A: Swift-XRT refined Analysis
  73. GRB 251108C: AstroSat CZTI detection
  74. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  75. GRB 251112B: MAXI/GSC detection
  76. Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
  77. Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
  78. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  79. GRB 251108B: Glowbug gamma-ray detection
  80. Swift Trigger 1413695: a possible GRB 251112A
  81. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  82. Fermi trigger No 784621743: Global MASTER-Net observations report
  83. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  84. GRB251111A: 1.3m DFOT optical upper limit
  85. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  86. GRB 251111A: Swift-XRT afterglow detection
  87. GRB 251111A: SVOM/VT optical observations with X-band data
  88. SVOM GRB251111.42: Global MASTER-Net observations report
  89. GRB 251111A: Swift-XRT observations
  90. SVOM GRB251111.22: Global MASTER-Net observations report
  91. GRB 251111A: EP-FXT counterpart detection
  92. GRB 251013C: Chandra X-ray observations and jet break detection
  93. GRB 251111A: SVOM/VT optical observations with VHF data
  94. GRB 251111A: KAIT optical upper limit
  95. GRB 251111A: LCO optical observation
  96. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  97. GRB 251111A: SVOM detection of a soft burst
  98. GRB 251103B: Swift-BAT refined analysis
  99. GRB 251106A: Swift/UVOT Upper Limits
  100. GRB 251105B: Insight-HXMT/HE detection

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