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"

28111 results found.

  1. GRB 250917B: Swift-BAT refined analysis
  2. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  3. GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
  4. GRB 250917B: Swift/UVOT Upper Limits
  5. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  6. GRB 250916A: Swift-XRT observations
  7. GRB 250916A: MAO/AZT-22 optical observations
  8. GRB 250916A: SAO RAS optical observations
  9. GRB 250916A : GIT optical observations
  10. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  11. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  12. GRB 250916A: Glowbug gamma-ray detection
  13. GRB250917B: WFST optical observations
  14. GRB 250917B: Fermi GBM Observation
  15. GRB 250917B: Swift-XRT observations
  16. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  17. GRB 250917B: Swift detection of a short burst
  18. GRB 250916A: AstroSat CZTI detection of a bright long burst
  19. EP250916a: Einstein Probe detection of an X-ray transient
  20. SVOM/sb25091517: SVOM detection of an X-ray transient
  21. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  22. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 250912A: Swift-XRT observations
  24. GRB250912A: VLT/HAWK-I follow-up observations
  25. GRB 250912A: Fermi GBM Observation
  26. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  27. GRB 250912A:SVOM/VT optical upper limit
  28. GRB 250912A: LCO optical upper limit
  29. EP250911a: Global MASTER-Net observations report
  30. GRB 250912A: SVOM detection of a burst
  31. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  32. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  33. EP250911a: Upper limit from Fermi-GBM Observations
  34. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  35. GRB 250911A: GECAM-B detection
  36. GRB 250911A: Swift-BAT refined analysis
  37. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  38. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  39. GRB 250910B: SVOM/GRM observation
  40. EP250911a: SVOM/VT optical observation
  41. GRB 250911A: MASTER optical counterpart observations
  42. EP250911a: SAO RAS optical observations
  43. GRB 250911A: Swift-XRT refined Analysis
  44. EP250911a: Swift-XRT observations
  45. EP250911a: Optical detection with Kinder observations
  46. GRB 250911A: Swift/UVOT Detection
  47. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  48. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  49. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  50. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  51. EP250911a: COLIBRÍ optical observations
  52. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  53. EP250911a: LCO optical counterpart discovery
  54. EP250911a: Einstein Probe detection of an X-ray transient
  55. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  56. GRB 250903A: SVOM/ECLAIRs refined analysis
  57. GRB 250911A: Enhanced Swift-XRT position
  58. GRB 250911A: Swift-XRT observations
  59. GRB 250911A: COLIBRÍ optical counterpart candidate
  60. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  61. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  62. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  63. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  64. GRB 250910A: SVOM/VT optical upper limit
  65. GRB 250910A: LCO optical upper limit
  66. EP250908b/EP#01709240653: Swift/UVOT Detection
  67. EP#01709240653: Swift-XRT observations
  68. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  69. EP250908c: SVOM/VT optical observation
  70. EP250908c: VLT/FORS2 optical counterpart identification
  71. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  72. EP250908b: SVOM/VT optical candidate
  73. Fermi GRB 250909A: Global MASTER-Net observations report
  74. EP250908c: Einstein Probe detection of an X-ray transient
  75. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  76. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  77. GRB 250907A: GECAM-B detection
  78. GRB 250905A: Swift-BAT refined analysis
  79. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  80. GRB 250903A: Swift-XRT afterglow detection
  81. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  82. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  83. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  84. EP250905a: Liverpool Telescope i-band upper limits
  85. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  86. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  87. EP250905a: Liverpool Telescope observations
  88. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  89. EP250905b: EP-WXT detection of a fast X-ray transient
  90. GRB 250905A: Swift-XRT refined Analysis
  91. EP250905a: JinShan likely optical counterpart detection
  92. GRB 250904A: Swift-BAT refined analysis
  93. GRB 250905A: Swift/UVOT Upper Limits
  94. GRB 250901A - SVOM/ECLAIRs refined analysis
  95. EP250905a: Einstein Probe detection of an X-ray transient
  96. GRB250904A: Liverpool Telescope upper limits
  97. GRB 250905A: Enhanced Swift-XRT position
  98. GRB 250904A: Swift/UVOT Detection
  99. GRB 250903A: Swift/UVOT detection
  100. GRB 250904A: Swift-XRT refined Analysis

Advanced

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