Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. 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"

32765 results found.

  1. EP251023b: Global MASTER-Net observations report
  2. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  3. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  4. GRB 251022A: GROWTH-India Telescope optical observations
  5. EP251023a: GROWTH-India Telescope optical observations
  6. GRB 251022A: Fermi GBM Observation
  7. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  8. GRB 251023A: Glowbug gamma-ray detection
  9. GRB 251023B: Glowbug gamma-ray detection
  10. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  11. EP251023a: Global MASTER-Net observations report
  12. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  13. IPN triangulation of GRB 251016B
  14. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  15. EP#01709247298: Swift-XRT counterpart detection
  16. EP251023a: COLIBRÍ optical observations
  17. GRB 251013C: further SAO RAS optical observations
  18. EP251023a: Keck/LRIS spectroscopic redshift z=2.232
  19. GRB 251022A: COLIBRÍ optical observations
  20. GRB 251013C: ISON-Castelgrande observatory optical observations
  21. GRB 251022A: MASTER OT detection
  22. GRB 251022A: DDOTI Optical Detection
  23. EP251021b/GRB 251021A: SVOM/VT optical candidate
  24. EP251023a: NOT optical counterpart detection
  25. Fermi GRB 251023A: Global MASTER-Net observations report
  26. EP251023a: GSP Optical Counterpart Detection
  27. EP251023a: Einstein Probe detection of an X-ray transient
  28. GRB 251022A: GOTO optical counterpart detection
  29. GRB 251022A: Fermi-LAT detection
  30. GRB 251022A: Tiled Swift observations
  31. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  32. EP251021b: BOOTES-7 optical upper limit
  33. GRB 250911A: MAXI/GSC detection
  34. LIGO/Virgo/KAGRA S251021u: Updated Sky localization
  35. GRB 251016A: SVOM/ECLAIRs refined analysis
  36. LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
  37. LIGO/Virgo/KAGRA S251018bi: Updated Sky localization
  38. Fermi-LAT gamma-ray observations of IceCube-251018A
  39. GRB 251017A : RAPAS follow-up observations
  40. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  41. GRB 251017A: COLIBRÍ optical observations of a late plateau
  42. IceCube-251018A: DDOTI Optical Upper Limit
  43. GRB 251017A: Swift-BAT refined analysis
  44. GRB 251016A: Fermi GBM Observation
  45. GRB 251018A: Fermi GBM Observation
  46. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  47. GRB 251016A: HXMT/HE detection
  48. LIGO/Virgo/KAGRA S251018bi: Identification of a GW compact binary merger candidate
  49. GRB 251017A: Swift/UVOT Detection
  50. GRB 251016A: Swift/UVOT Detection
  51. GRB 251018A: Swift/UVOT Detection
  52. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  53. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  54. GRB 251016A: VLT/FORS2 Optical Observation
  55. GRB 251017A: COLIBRÍ photometric redshift
  56. GRB 251018A: MASTER OT detection
  57. GRB 251018A: TRT optical afterglow detection
  58. Swift GRB 251018A: Global MASTER-Net observations report
  59. GRB 251017A: SVOM/VT optical observation
  60. GRB 251011A: Fermi GBM Observation
  61. GRB 251017A: OHP/T193 i-band observations
  62. GRB 251013C: OHP/T193 third epoch optical observations and detected rebrightening
  63. GRB 251017A: J-band detection with WINTER
  64. GRB 251017A: Glowbug gamma-ray detection
  65. GRB 251013C: Liverpool Telescope observations
  66. GRB 251013C: Leavitt Observatory optical photometry
  67. Fermi GRB 251016B: Global MASTER-Net observations report
  68. GRB 251017A: JinShan observations of the optical afterglow
  69. Swift GRB 251017A: Global MASTER-Net observations report
  70. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  71. Swift Trigger 1404295 is not a GRB
  72. GRB 251016A: AstroSat CZTI detection of a short burst
  73. GRB 251017A: COLIBRÍ Early Afterglow Detection
  74. GRB 251016B: AstroSat CZTI detection
  75. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  76. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  77. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  78. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  79. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  80. GRB 251007B: Swift-BAT refined analysis
  81. GRB 251014D: Swift-BAT refined analysis
  82. GRB 251016A: BOOTES-6/DPRT optical upper limit
  83. GRB 251016A: Glowbug gamma-ray detection of a short burst
  84. GRB 251013C: VLA detection
  85. Fermi GRB 251016A: Global MASTER-Net observations report
  86. LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
  87. GRB 251014B: PRIME J-band upper limit
  88. Upper limits from a search for additional neutrino events in IceCube
  89. GRB 251013C: Kilonova-Catcher optical afterglow detection
  90. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  91. GRB 251013D: Swift/UVOT Observations
  92. GRB 251013C: Swift/UVOT Detection
  93. Konus-Wind detection of GRB 251007A
  94. GRB 251013C, GCN Circular 42267, errata corrige
  95. GRB 251013C: detection of a radio counterpart at 15.5GHz
  96. GRB 251013C: SVOM/ECLAIRs refined analysis
  97. GRB 251014B: Swift/UVOT Upper Limits
  98. GRB 251014B: VLT/FORS2 Optical Observation
  99. GRB 251014D: Swift/UVOT Upper Limits
  100. GRB 251013C: MAO/AZT-22 optical observations

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