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"

28300 results found.

  1. Fast X-ray Transient EP240801a: GMRT radio observations
  2. GRB 240912A: Swift detection of a burst with an optical counterpart
  3. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  4. GRB 240910A: JinShan optical observations
  5. IPN triangulation of GRB 240905B (short)
  6. GRB 240825A: 7DT Optical Upper Limit
  7. GRB 240905E: SVOM/VT optical observations
  8. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  9. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  10. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  11. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  12. GRB 240910A: SVOM/GRM observation
  13. EP240908a: Mondy and AbAO follow-up observations
  14. EP240908a: Updates on the WXT detection result around the trigger time
  15. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  17. GRB 240905B: Fermi GBM Observation
  18. Fermi trigger No 747553301: Global MASTER-Net observations report
  19. EP240908a: TRT optical upper limit
  20. EP240908a: EP detection of a fast X-ray transient
  21. LIGO/Virgo/KAGRA S240908dg: Updated Sky localization
  22. LIGO/Virgo/KAGRA S240908bs: Updated Sky localization
  23. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S240907cg: Updated Sky localization
  26. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  27. GRB 240905E: GIT optical upper limit
  28. GRB 240905B: Swift-XRT observations
  29. GRB 240905E: Gaoyazi/GOT optical upper limits
  30. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  31. GRB 240905E: J-band observations with WINTER
  32. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  33. GRB 240905E: AKO Optical Upper Limit
  34. GRB 240905E: SVOM/C-GFT optical upper limit
  35. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  36. GRB 240905E: NOT optical upper limits
  37. GRB 240905E: REM optical/NIR upper limits
  38. GRB 240902B: AstroSat CZTI detection of a long burst
  39. GRB 240905E: Swift-XRT refined Analysis
  40. GRB 240902A: AstroSat CZTI detection of a long burst
  41. GRB 240905E: LCOGT Optical Upper Limit
  42. GRB 240905E: Swift/UVOT Upper Limits
  43. GRB 240905E: SAO RAS optical upper limit
  44. GRB 240905E: Nanshan/HMT optical upper limit
  45. GRB 240905E: Swift detection of a burst
  46. GRB 240905B: AstroSat CZTI detection and localization
  47. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  49. LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
  50. GRB 240828A: GECAM detection
  51. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  52. GRB 240825A: MeerLICHT afterglow detection
  53. GRB 240828A: SAO RAS AS-500(2) optical observations
  54. GRB 240821A: VLT spectroscopic observations
  55. GRB 240825A: TSHAO Optical Upper Limit
  56. GRB240828B: REM optical/NIR upper limits
  57. GRB 240828B: AbAO optical upper limit
  58. GRB 240825A: SOAR observations
  59. GRB 240828B: Mephisto optical upper limit
  60. GRB 240828B: GRANDMA Optical Upper Limit
  61. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  63. GRB 240829A: Swift-BAT refined analysis
  64. GRB 240825A: Swift-BAT refined analysis
  65. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  66. GRB 240828B: J-band upper limit from WINTER
  67. GRB 240828B: GMG Optical Upper Limit
  68. GRB 240828B: SVOM/C-GFT optical upper limit
  69. GRB 240828B: SAO RAS optical upper limit
  70. GRB 240828A: SAO RAS optical observations
  71. Fermi trigger No 746587425: Global MASTER-Net observations report
  72. GRB 240828A: Fermi GBM Observation
  73. GRB 240828A: KAIT Optical Afterglow Candidate
  74. GRB 240825A: SVOM/VT optical detection
  75. GRB 240828A: Swift-XRT afterglow detection
  76. GRB 240825A: further SAO RAS optical observations
  77. GRB 240825A: iTelescope optical observations
  78. GRB 240828B: Swift-XRT afterglow detection
  79. GRB 240829A: Swift detection of a burst
  80. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  81. GRB 240825A: Upper limits from a neutrino search with IceCube
  82. GRB 240821A: PRIME near-infrared observations
  83. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  84. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  85. GRB 240825A: SAO RAS optical observations
  86. GRB 240824A: GIT optical upper limit
  87. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  88. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  89. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  90. GRB 240825A: GMG Continued Optical Observation on the Second Night
  91. GRB 240825A: PRIME near-infrared detection
  92. GRB 240825A: Fermi GBM Observation
  93. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  94. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  95. GRB 240825A: Swift/UVOT Detection
  96. GRB 240825A: REM detection of the optical/NIR afterglow
  97. GRB 240825A: Swift-XRT refined Analysis
  98. GRB 240825A: VLT/X-shooter redshift
  99. GRB 240825A: Montarrenti Observatory optical observations
  100. GRB 240825A: Enhanced Swift-XRT position

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