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"

28102 results found.

  1. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  2. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  3. GRB 250916A: Glowbug gamma-ray detection
  4. GRB250917B: WFST optical observations
  5. GRB 250917B: Fermi GBM Observation
  6. GRB 250917B: Swift-XRT observations
  7. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  8. GRB 250917B: Swift detection of a short burst
  9. GRB 250916A: AstroSat CZTI detection of a bright long burst
  10. EP250916a: Einstein Probe detection of an X-ray transient
  11. SVOM/sb25091517: SVOM detection of an X-ray transient
  12. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  13. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 250912A: Swift-XRT observations
  15. GRB250912A: VLT/HAWK-I follow-up observations
  16. GRB 250912A: Fermi GBM Observation
  17. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  18. GRB 250912A:SVOM/VT optical upper limit
  19. GRB 250912A: LCO optical upper limit
  20. EP250911a: Global MASTER-Net observations report
  21. GRB 250912A: SVOM detection of a burst
  22. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  23. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  24. EP250911a: Upper limit from Fermi-GBM Observations
  25. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  26. GRB 250911A: GECAM-B detection
  27. GRB 250911A: Swift-BAT refined analysis
  28. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  29. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  30. GRB 250910B: SVOM/GRM observation
  31. EP250911a: SVOM/VT optical observation
  32. GRB 250911A: MASTER optical counterpart observations
  33. EP250911a: SAO RAS optical observations
  34. GRB 250911A: Swift-XRT refined Analysis
  35. EP250911a: Swift-XRT observations
  36. EP250911a: Optical detection with Kinder observations
  37. GRB 250911A: Swift/UVOT Detection
  38. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  39. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  40. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  41. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  42. EP250911a: COLIBRÍ optical observations
  43. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  44. EP250911a: LCO optical counterpart discovery
  45. EP250911a: Einstein Probe detection of an X-ray transient
  46. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  47. GRB 250903A: SVOM/ECLAIRs refined analysis
  48. GRB 250911A: Enhanced Swift-XRT position
  49. GRB 250911A: Swift-XRT observations
  50. GRB 250911A: COLIBRÍ optical counterpart candidate
  51. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  52. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  53. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  54. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  55. GRB 250910A: SVOM/VT optical upper limit
  56. GRB 250910A: LCO optical upper limit
  57. EP250908b/EP#01709240653: Swift/UVOT Detection
  58. EP#01709240653: Swift-XRT observations
  59. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  60. EP250908c: SVOM/VT optical observation
  61. EP250908c: VLT/FORS2 optical counterpart identification
  62. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  63. EP250908b: SVOM/VT optical candidate
  64. Fermi GRB 250909A: Global MASTER-Net observations report
  65. EP250908c: Einstein Probe detection of an X-ray transient
  66. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  67. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  68. GRB 250907A: GECAM-B detection
  69. GRB 250905A: Swift-BAT refined analysis
  70. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  71. GRB 250903A: Swift-XRT afterglow detection
  72. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  73. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  74. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  75. EP250905a: Liverpool Telescope i-band upper limits
  76. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  77. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  78. EP250905a: Liverpool Telescope observations
  79. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  80. EP250905b: EP-WXT detection of a fast X-ray transient
  81. GRB 250905A: Swift-XRT refined Analysis
  82. EP250905a: JinShan likely optical counterpart detection
  83. GRB 250904A: Swift-BAT refined analysis
  84. GRB 250905A: Swift/UVOT Upper Limits
  85. GRB 250901A - SVOM/ECLAIRs refined analysis
  86. EP250905a: Einstein Probe detection of an X-ray transient
  87. GRB250904A: Liverpool Telescope upper limits
  88. GRB 250905A: Enhanced Swift-XRT position
  89. GRB 250904A: Swift/UVOT Detection
  90. GRB 250903A: Swift/UVOT detection
  91. GRB 250904A: Swift-XRT refined Analysis
  92. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  93. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  94. EP detected a brightening of LMXB 1ES 1735-26.9
  95. GRB 250905A: KAIT optical upper limit
  96. GRB 250905A: Swift detection of a burst
  97. GRB 250904A: Enhanced Swift-XRT position
  98. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 250904A: TRT optical counterpart detection
  100. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations

Advanced

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