Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

5401 results found.

  1. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  2. GRB 241030B: AKO Optical Afterglow Detection
  3. GRB 241030B: Prompt enhanced Swift-XRT position
  4. GRB 241030A: Fermi-LAT detection
  5. GRB 241026A: LBT optical observations
  6. GRB 241030A: SVOM/VT optical afterglow observations
  7. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  8. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  9. GRB 241030A: Fermi GBM Final Real-time Localization
  10. EP241021a: SAO RAS observations of rebrightening
  11. GRB 241029A: GOTO optical afterglow detection
  12. EP 241026b: LBT possible optical counterpart (brightening source)
  13. EP EP241026b: Global MASTER-Net observations report
  14. Fermi GRB 241026A: Global MASTER-Net observations report
  15. GRB 241025A: COLIBRÍ Detection of the Afterglow
  16. Fermi GRB 241025A: Global MASTER-Net observations report
  17. GRB 241025A : SVOM/VT optical afterglow observations
  18. Fermi trigger No 750788395: Global MASTER-Net observations report
  19. Fermi GRB 241016A: Global MASTER-Net observations report
  20. IceCube Alert 241016.04: Global MASTER-Net observations report
  21. GRB 241009A: LCO optical upper limits
  22. GRB 241006A: ATCA Radio Upper Limits
  23. Fermi trigger No 750211959: Global MASTER-Net observations report
  24. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  25. IceCube Alert 241006.94: Global MASTER-Net observations report
  26. Fermi trigger No 749721670: Global MASTER-Net observations report
  27. Fermi trigger No 749630753: Global MASTER-Net observations report
  28. GRB 241001A : SVOM/VT optical detection
  29. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  30. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  31. GRB 241002B: GOTO optical counterpart candidate
  32. GRB 241002A: 1.5m OSN optical upper limit
  33. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  34. EP EP240930a: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  36. Fermi GRB 240929A: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo S240919bn: GOTO optical upper limits
  39. EP240919a / GRB 240919A: KAIT optical upper limit
  40. EP240919a: GOTO optical upper limits
  41. EP EP240918a: Global MASTER-Net observations report
  42. GRB 240916A: NOT optical observation
  43. GRB 240913B: Fermi GBM Final Real-time Localization
  44. Fermi GRB 240913A: Global MASTER-Net observations report
  45. GRB 240913A: Fermi GBM Final Real-time Localization
  46. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  47. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  48. GRB 240905E: Swift-XRT refined Analysis
  49. GRB 240905E: Swift detection of a burst
  50. GRB 240825A: MeerLICHT afterglow detection
  51. Fermi trigger No 746882332: Global MASTER-Net observations report
  52. Fermi trigger No 746587425: Global MASTER-Net observations report
  53. GRB 240828A: KAIT Optical Afterglow Candidate
  54. GRB 240825A: iTelescope optical observations
  55. GRB 240829A: Swift detection of a burst
  56. Swift GRB240829.16: Global MASTER-Net observations report
  57. LAT GRB240828.62: Global MASTER-Net observations report
  58. Fermi GRB 240828A: Global MASTER-Net observations report
  59. Fermi trigger No 746438824: Global MASTER-Net observations report
  60. GRB 240825A: ALMA detection
  61. GRB 240825A: SAO RAS optical observations
  62. GRB 240825A: VLT/X-shooter redshift
  63. GRB 240824A: KAIT optical upper limit
  64. GRB 240824A: Swift detection of a burst
  65. GRB 240821A: Swift-XRT observations
  66. Fermi GRB 240821A: Global MASTER-Net observations report
  67. Fermi trigger No 746019401: Global MASTER-Net observations report
  68. Fermi trigger No 745935375: Global MASTER-Net observations report
  69. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  70. GRB 240819A: Swift-XRT observations
  71. EP240820a: TRT optical upper limit
  72. GRB 240819A: KAIT optical upper limit
  73. EP240816b: Liverpool Telescope optical follow-up observations
  74. GRB 240814A: Fermi GBM Final Real-time Localization
  75. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  76. GRB 240812D: Fermi GBM Final Real-time Localization
  77. EP240801a: Assy-Turgen optical observations
  78. Fermi trigger No 745057312: Global MASTER-Net observations report
  79. EP240807a: STEP/T80S optical limits
  80. EP EP240807a: Global MASTER-Net observations report
  81. EP EP240806a: Global MASTER-Net observations report
  82. GRB 240801A: GRBAlpha detection
  83. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  84. Fermi trigger No 744629911: Global MASTER-Net observations report
  85. Improved IPN triangulation of GRB 240802A / EP 240802a
  86. GRB 240626B: VZLUSAT-2 detection
  87. Fermi trigger No 744544656: Global MASTER-Net observations report
  88. EP240801a: BTA BVRI photometry
  89. Fermi GRB 240805A: Global MASTER-Net observations report
  90. EP240801a: Continued optical observations at ZTSh (CraO)
  91. EP240804a: LCOGT optical counterpart detection
  92. Fermi GRB 240804A: Global MASTER-Net observations report
  93. EP240802a: Montarrenti Observatory optical upper limit
  94. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  95. Fermi trigger No 744278264: Global MASTER-Net observations report
  96. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  97. EP240801a: Leavitt Observatory optical observations
  98. EP240801a: GMG observation
  99. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  100. Fermi GRB 240801A: Global MASTER-Net observations report

Advanced

Download all Circulars as a .tar.gz archive:
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