Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

45483 results found.

  1. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  2. GRB 241030B: Montarrenti Observatory optical upper limit
  3. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  4. EP241026b: Liverpool Telescope optical follow-up
  5. Fermi trigger No 752083996: Global MASTER-Net observations report
  6. GRB 241030A: SAO RAS optical observations
  7. GRB 241030A: Fermi GBM Observation
  8. EP241021a: AMI-LA radio detection
  9. GRB 241030B : GIT optical upper limits
  10. GRB 241030B: LCOGT Optical Upper Limits
  11. GRB 241030B: Swift-BAT refined analysis
  12. GRB 241030A: Swift-BAT refined analysis
  13. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  14. GRB 241030B: Swift/UVOT Detection
  15. EP EP241030a: Global MASTER-Net observations report
  16. GRB 241029A: LCO optical detection
  17. Fermi trigger No 752006065: Global MASTER-Net observations report
  18. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  19. Swift GRB241030.77: Global MASTER-Net observations report
  20. GRB 241030B: SVOM/GRM observation
  21. GRB 241030B : MITSuME Akeno optical upper limits
  22. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  23. GRB 241030B: SVOM/VT optical afterglow observations
  24. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  25. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  26. GRB241030B: Fermi GBM Observation
  27. GRB 241030B: BTA observations
  28. GRB 241029A: SVOM/VT optical afterglow observations
  29. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  30. GRB 241030B: Enhanced Swift-XRT position
  31. GRB 241030B: optical observations from the INAF Asiago Observatory
  32. EP241021a: Swift-UVOT detection
  33. GRB241030B: GRANDMA/TAROT Upper Limit
  34. GRB 241030A: Swift-XRT refined Analysis
  35. GRB 241030B: SAO RAS optical observations
  36. GRB 241030B: AKO Optical Afterglow Detection
  37. GRB 241030B: Nanshan/HMT optical afterglow detection
  38. GRB 241030B: SVOM/ECLAIRs detection of a burst
  39. GRB 241030B: Prompt enhanced Swift-XRT position
  40. Konus-Wind detection of GRB 241030A
  41. GRB 241030B: Swift detection of a burst
  42. GRB 241030B: Fermi GBM Final Real-time Localization
  43. GRB 241030A: Fermi-LAT detection
  44. GRB 240912A: radio detection with the VLA
  45. Fermi GRB 241030A: Global MASTER-Net observations report
  46. GRB 241030A: AKO Optical Afterglow Detection
  47. Swift GRB 241030A: Global MASTER-Net observations report
  48. GRB 241030A: Swift/UVOT Detection
  49. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  50. GRB 241030A: SVOM/GRM observation
  51. GRB 241026A: Swift-BAT refined analysis
  52. GRB 241030A: SVOM/C-GFT optical observations
  53. GRB 241026A: LBT optical observations
  54. EP241021a: Optical rebrightening observations with Mephisto
  55. EP241026b: EP-FXT follow-up observation
  56. GRB 241030A: Multiband optical detection with Mephisto
  57. GRB 241030A: SVOM/VT optical afterglow observations
  58. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  59. GRB 241030A : MITSuME Akeno optical afterglow detection
  60. GRB 241030A: Enhanced Swift-XRT position
  61. GRB 241029A: GROWTH-India Telescope optical follow up
  62. GRB 241030A: TRT optical observations
  63. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  64. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  65. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  66. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  67. GRB 241030A: Fermi GBM Final Real-time Localization
  68. GRB 241029A: SAO RAS optical observations
  69. GRB 241026A: SAO RAS optical observations
  70. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  71. EP241021a: SAO RAS observations of rebrightening
  72. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  73. EP241021a: ATCA radio observations
  74. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  75. GRB 241026A: Swift/UVOT Upper Limits
  76. GRB 241029A: Swift-XRT observations
  77. GRB 241029A: Fermi GBM Observation
  78. GRB 241029A: AKO Optical Afterglow Detection
  79. GRB 241029A: GOTO optical afterglow detection
  80. EP241021a: continued SOAR observations confirm optical rebrightening
  81. GRB 241029A: MASTER early optical counterpart detection
  82. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  83. GRB 241029A: Mephisto observations
  84. EP 241026b: LBT possible optical counterpart (brightening source)
  85. GRB 241029A: TRT optical afterglow candidate detection
  86. GRB 241029A: Swift ToO observations
  87. GRB 241029A: SVOM/GRM observation
  88. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  89. Fermi trigger No 751861204: Global MASTER-Net observations report
  90. GRB 241029A: Fermi GBM Final Real-time Localization
  91. GRB 240821A: Keck/LRIS spectroscopic observations
  92. EP241021a: Gemini-South detection of optical rebrightening
  93. GRB 241026A: the 100th GRB detected by GRBAlpha
  94. GRB 241026A: TNOT optical counterpart detection
  95. Konus-Wind detection of GRB 241025A
  96. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  97. GRB 241026A: LBT redshift confirmation
  98. GRB 241026A: GECAM detection
  99. GRB 241025A: further SAO RAS optical observations
  100. GRB 241026A: BTA and Zeiss-1000 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