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"

45512 results found.

  1. EP250702a: WFST optical observations
  2. EP250704a: COLIBRÍ optical counterpart candidate
  3. EP250704a: Einstein Probe detection of an X-ray transient
  4. GRB 250704B: SVOM/GRM observation of a short burst
  5. GRB 250702F: optical photometry from Konkoly
  6. GRB 250704A: REM detection of the optical afterglow
  7. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  8. GRB 250702F: SVOM/VT optical observation
  9. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  10. GRB 250704A: SVOM detection of a burst
  11. GRB 250702F: Swift/UVOT Detection
  12. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  13. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  14. Fermi GRB 250703A: Global MASTER-Net observations report
  15. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  16. GRB 250702F: Swift-XRT refined Analysis
  17. GRB 250702F: Fermi GBM Observation
  18. GRB 250702F: Leavitt Observatory optical observations
  19. GRB 250702F: AKO Optical Afterglow Detection
  20. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  21. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  22. GRB 250702A: GECAM-B detection
  23. GRB 250702F: Skynet Optical Observations
  24. GRB 250424A: VIRT Optical Upper Limit
  25. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  26. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  27. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  28. GRB 250702F: TRT Optical Observation
  29. GRB 250703A: DDOTI Optical Upper Limit
  30. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  31. GRB 250702F: REM optical afterglow detection
  32. EP250702a: Global MASTER-Net observations report
  33. GRB 250702F: DDOTI Optical Observation
  34. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  35. GRB 250703A: Fermi GBM Final Real-time Localization
  36. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  37. GRB 250702F: COLIBRÍ Observations of the Afterglow
  38. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  39. Fermi GRB 250702E: Global MASTER-Net observations report
  40. Fermi GRB 250702B: Global MASTER-Net observations report
  41. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  42. GRB 250702F: Enhanced Swift-XRT position
  43. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  44. GRB 250702F: NOT observations of the optical afterglow
  45. GRB 250702F: MASTER optical afterglow observation
  46. Fermi GRB 250702F: Global MASTER-Net observations report
  47. Fermi GRB 250702C: Global MASTER-Net observations report
  48. GRB 250702F: GOTO optical counterpart detection
  49. GRB 250702F: Ondrejov D50 optical afterglow detection
  50. GRB 250702F: Swift detection of a burst with an optical counterpart
  51. Swift GRB 250702F: Global MASTER-Net observations report
  52. GRB 250702F: Fermi GBM Final Real-time Localization
  53. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  54. GRB 250702E: Fermi GBM Final Real-time Localization
  55. Konus-Wind detection of GRB 250627A
  56. IPN triangulation of GRB 250627A (short)
  57. GRB 250702A: Fermi GBM Detection
  58. GRB 250702D: Fermi GBM Final Localization Correction
  59. GRB 250702C: Fermi GBM Final Real-time Localization
  60. LIGO/Virgo/KAGRA S250702n: Identification of a GW compact binary merger candidate
  61. GRB 250702B: Fermi GBM Final Real-time Localization
  62. GRB 250702A: BALROG localization (Fermi Trigger 773142852 / GRB 250702413)
  63. GRB 250702A: Fermi GBM Final Real-time Localization
  64. LIGO/Virgo/KAGRA S250701bq: Identification of a GW compact binary merger candidate
  65. LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate
  66. Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB
  67. GRB 250628B: Swift-XRT observations
  68. Fermi Gamma-ray Burst Monitor trigger 772981768/250630548 is not a GRB
  69. GRB 250628B: SVOM/VT optical upper limit
  70. GRB 250628B: EP-FXT counterpart detection
  71. LIGO/Virgo/KAGRA S250629bs: Updated Sky localization
  72. GRB 250627A: Insight-HXMT detection
  73. GRB 250627A: SVOM/GRM detection of a short burst
  74. LIGO/Virgo/KAGRA S250629ae: Updated Sky localization
  75. LIGO/Virgo/KAGRA S250629bs: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate (duplicate submission)
  77. LIGO/Virgo/KAGRA S250629ae: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S250628am: Updated Sky localization
  79. GRB 250628A: REM optical/NIR upper limits
  80. GRB 250628C: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate
  82. GRB 250628B: SVOM detection of a long burst
  83. Fermi Gamma-ray Burst Monitor trigger 772811638/250628579 is not a GRB
  84. GRB 250625A: VLT/X-shooter spectroscopic observations at the afterglow position
  85. GRB 250628A: VLT/X-shooter upper limits
  86. GRB 250628A: Swift/UVOT Upper Limits
  87. GRB 250628A: Swift-XRT refined Analysis
  88. Fermi GRB 250626A: Global MASTER-Net observations report
  89. Swift GRB 250628A: Global MASTER-Net observations report
  90. GRB 250628A: Enhanced Swift-XRT position
  91. GRB 250628A: Swift detection of a burst
  92. GRB 250625A: Swift-BAT refined analysis
  93. GRB 250625A: Leavitt Observatory afterglow detection
  94. Fermi Gamma-ray Burst Monitor trigger 772732642/250627665 is not a GRB
  95. Fermi Gamma-ray Burst Monitor trigger 772720540/250627525 is not a GRB
  96. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  97. The EP-WXT trigger 01709179435 is likely a new outburst of the CV SS Cyg
  98. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  99. GRB 250626A: Fermi GBM Final Real-time Localization
  100. Fermi Gamma-ray Burst Monitor trigger 772647532/250626680 is not a GRB

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