Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

4001 results found.

  1. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  2. Fermi GRB 241118A: Global MASTER-Net observations report
  3. EP241113b: Global MASTER-Net observations report
  4. SVOM/GRM detection of a short burst from SGR 1E1841-045
  5. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  6. Fermi trigger No 752990530: Global MASTER-Net observations report
  7. Fermi trigger No 752878030: Global MASTER-Net observations report
  8. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  9. EP241107a: FTW Optical and NIR observations of the optical counterpart
  10. GRB 241030A: Mondy optical observations
  11. Fermi GRB 241105A: Global MASTER-Net observations report
  12. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  13. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  14. EP241021a: OHP/T193 further optical observations
  15. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  16. EP241103a: Global MASTER-Net observations report
  17. GRB 241029A: GRBAlpha detection
  18. GRB241030A: OHP/T193 optical observations
  19. GRB 241029A: LCO optical detection
  20. Fermi trigger No 752006065: Global MASTER-Net observations report
  21. EP241021a: Swift-UVOT detection
  22. EP241021a: Optical rebrightening observations with Mephisto
  23. GRB 241029A: GROWTH-India Telescope optical follow up
  24. GRB 241029A: SAO RAS optical observations
  25. GRB 241026A: SAO RAS optical observations
  26. EP241021a: SAO RAS observations of rebrightening
  27. GRB 241029A: Fermi GBM Observation
  28. GRB 241029A: AKO Optical Afterglow Detection
  29. GRB 241029A: GOTO optical afterglow detection
  30. GRB 241029A: MASTER early optical counterpart detection
  31. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  32. GRB 241029A: Mephisto observations
  33. GRB 241029A: TRT optical afterglow candidate detection
  34. GRB 241029A: SVOM/GRM observation
  35. Fermi trigger No 751861204: Global MASTER-Net observations report
  36. GRB 241029A: Fermi GBM Final Real-time Localization
  37. Fermi GRB 241026A: Global MASTER-Net observations report
  38. EP241021a: optical follow-up observations with Xinglong Observatory
  39. Fermi trigger No 751554401: Global MASTER-Net observations report
  40. EP241025a (GRB 241025A): EP observations update
  41. GRB 241018A: Mondy optical upper limit
  42. Fermi trigger No 750788395: Global MASTER-Net observations report
  43. GRB 241013B: Fermi GBM Observation
  44. GRB 241013A: Fermi GBM Observation
  45. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  46. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  47. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  49. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  50. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  51. Fermi GRB 241002B: Global MASTER-Net observations report
  52. GRB 241001A: Swift-XRT observations
  53. GRB 240929A: GRBAlpha detection
  54. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  55. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  56. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  57. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  58. GRB 240929A : Leavitt Observatory optical upper limit
  59. Fermi GRB 240930B: Global MASTER-Net observations report
  60. Fermi GRB 240930A: Global MASTER-Net observations report
  61. Fermi trigger No 749339671: Global MASTER-Net observations report
  62. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  63. GRB 240929A long GRB detected by INTEGRAL
  64. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  65. Fermi GRB 240929A: Global MASTER-Net observations report
  66. GRB 240929A: Fermi GBM Final Real-time Localization
  67. Integral GRB240929.83: Global MASTER-Net observations report
  68. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  69. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  70. EP240913a/GRB 240913C: 1.6m Mephisto observations
  71. EP240918a: SVOM/VT upper limit
  72. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  73. GRB 240821A: radio observation with the VLA
  74. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  75. EP240913a: JinShan optical upper limits
  76. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  77. Fermi trigger No 747553301: Global MASTER-Net observations report
  78. GRB 240905B: GOTO optical upper limits
  79. GRB 240905E: Swift detection of a burst
  80. Fermi GRB 240905B: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  82. Fermi trigger No 746923430: Global MASTER-Net observations report
  83. GRB 240828A: SAO RAS AS-500(2) optical observations
  84. GRB 240829B: GRBAlpha detection
  85. GRB 240828B: AbAO optical upper limit
  86. GRB 240828B: GRANDMA Optical Upper Limit
  87. GRB 240825A: MeerKAT detection
  88. GRB 240828B: SAO RAS optical upper limit
  89. GRB 240828A: SAO RAS optical observations
  90. Fermi trigger No 746587425: Global MASTER-Net observations report
  91. GRB 240829B: Fermi GBM Final Localization
  92. GRB 240629A: First GRB Detected by BurstCube
  93. GRB 240828A: KAIT Optical Afterglow Candidate
  94. Swift GRB240829.16: Global MASTER-Net observations report
  95. LAT GRB240828.62: Global MASTER-Net observations report
  96. Fermi trigger No 746438824: Global MASTER-Net observations report
  97. GRB 240825A: SAO RAS optical observations
  98. GRB 240824A: GIT optical upper limit
  99. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  100. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit

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