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"

20408 results found.

  1. GRB 250403A: Montarrenti Observatory optical detection
  2. GRB 250403A: KAIT optical observations
  3. EP250404a: AKO Optical Afterglow Detection
  4. EP250404a: LAST detection of optical counterpart
  5. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  6. GRB 250327B: VIRT Optical Upper Limit
  7. EP250404a: Mephisto multi-band optical detection
  8. EP250321A: J band upper limit by SYSU 80cm telescope
  9. EP250404a: BOOTES-4/JGT optical afterglow detection
  10. EP250404a: Nanshan/HMT optical counterpart detection
  11. EP250404a: Einstein Probe detection of an X-ray transient
  12. GRB 250404A: Fermi GBM Final Real-time Localization
  13. GRB 250403A: Swift/UVOT Detection
  14. GRB 250402A: Swift/UVOT Upper Limits
  15. EP250402a: Optical upper limit with Kinder observations
  16. GRB 250403A: REM NIR afterglow detection
  17. GRB 250403A: LCO optical counterpart detection
  18. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  19. GRB 250403A: JinShan optical observations
  20. GRB 250403A: Optical counterpart detection by LCO.
  21. GRB 250322A: 10 GHz VLA radio upper limits
  22. GRB 250402A: NUTTelA-TAO Early Optical Limits
  23. GRB 250403A: GMG Optical Observation
  24. GRB 250403A: 1.6m Mephisto multi-band optical detection
  25. GRB 250403A: SVOM/C-GFT optical observations
  26. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  27. GRB 250402A: REM optical/NIR upper limits
  28. GRB 250402A: LCO optical counterpart detection
  29. EP250402a: Einstein Probe detection of a fast X-ray transient
  30. GRB 250402A: SVOM/VT optical counterpart
  31. GRB 250402A: SVOM detection of a burst
  32. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  33. GRB 250329B: Swift/UVOT Upper Limit
  34. GRB 250329A: Swift/UVOT Upper Limit
  35. GRB 250327B: Swift/UVOT Detection
  36. GRB 250327A: Swift/UVOT Upper Limits
  37. GRB 250331E: SVOM/GRM observation
  38. GRB 250327B: Kilonova-Catcher Observations
  39. GRB250331D: AbAO optical observations
  40. GRB 250331C: Swift/UVOT Upper Limits
  41. GRB 250331B: Swift/UVOT Upper Limits
  42. GRB 250328A: AbAO AS-32 Optical Observations
  43. GRB 250219A: NOT candidate host galaxy detection
  44. GRB 250331D: Swift-XRT observations
  45. GRB 250331B: Swift-XRT refined Analysis
  46. GRB 250331B: Swift-XRT refined Analysis
  47. GRB 250330B: SVOM/GRM observation of a short burst
  48. Fermi GRB 250331E: Global MASTER-Net observations report
  49. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  50. GRB 250331C: Enhanced Swift-XRT position
  51. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  52. GRB 250331B: Enhanced Swift-XRT position
  53. GRB 250320C : SVOM detection of a burst through offline search
  54. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  55. GRB 250330A: VLT/FORS2 Afterglow Detection
  56. GRB20250327B: 45th Parallel Observatory upper limit
  57. GRB 250328A: Swift/UVOT Detection
  58. GRB 250328A: Swift-XRT refined Analysis
  59. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  60. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  61. GRB 250331C: Swift detection of a burst
  62. GRB 250331B: Swift detection of a burst
  63. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  64. GRB 250330A: Swift/UVOT Upper Limits
  65. GRB 250330A: Swift-XRT afterglow detection
  66. GRB 250328A: 1.6m Mephisto optical observations
  67. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  68. GRB 250330A: VLT/FORS2 Optical Observations
  69. GRB 250330A: Prompt Swift-XRT position
  70. GRB 250329B: Swift-XRT afterglow detection
  71. GRB 250330A: Swift detection of a burst
  72. GRB 250329B: SVOM/C-GFT optical upper limit
  73. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  74. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  75. GRB250329A: REM optical afterglow detection
  76. GRB 250329B: GWAC-F50A optical upper limit
  77. GRB 250329A: Swift-XRT afterglow detection
  78. GRB 250328A: SVOM/VT optical observation
  79. GRB 250329A: Fading optical counterpart detection by LCO.
  80. GRB 250328A: SVOM/C-GFT optical upper limit
  81. GRB 250328A: SVOM/COLIBRÍ (F-GFT) optical afterglow candidate
  82. GRB 250329A: VLT/X-shooter redshift z = 2.921
  83. GRB 250329A: SVOM/VT optical counterpart confirmation
  84. GRB 250329A: SVOM detection of a burst
  85. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  86. GRB 250327B: J-band observations with WINTER
  87. GRB 250327B: LCO optical counterpart detection
  88. LIGO/Virgo/KAGRA S250328ae: NED Galaxies in the 4-Update Localization Volume
  89. EP250302a: SPI-ACS/INTEGRAL Upper Limit
  90. GRB 250327B: CrAO and SAO RAS Optical Observations
  91. EP250315a: Pan-STARRS r and i-band imaging and photometry
  92. GRB 250327b: Liverpool Telescope optical observations
  93. GRB 250322A: GRANDMA/TNOT optical upper limits
  94. GRB 250327A: SVOM/VT upper limits on the XRT position
  95. LIGO/Virgo/KAGRA S250328ae: Identification of a GW compact binary merger candidate
  96. GRB 250327B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  97. GRB 250327B: Las Cumbres optical counterpart detection
  98. GRB 250327B: 1.6m Mephisto optical observations
  99. GRB 250327B: NOT spectroscopic redshift z = 3.035
  100. GRB 250327B: SVOM/VT optically bright counterpart

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