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"

20970 results found.

  1. GRB 241017A/sb24101702: Mephisto optical upper limit
  2. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  3. GRB 241018A: GROWTH-India telescope optical upper limit
  4. GRB 241018A: Swift-XRT observations
  5. GRB 241018A: REM optical/NIR upper limits
  6. GRB 241018A: NOT optical observations
  7. GRB 241017A: SVOM/VT follow-up and optical upper limit
  8. GRB 241018A: SVOM/VT follow-up and optical candidate
  9. GRB 241018A: Swift ToO observations
  10. GRB 241018A: X-ray afterglow candidate observed by MXT
  11. GRB 241016B: Fermi GBM Observations
  12. GRB 241017A: Swift-XRT observations
  13. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  14. GRB241017A: TOO Observations by SVOM/MXT
  15. GRB 241017A: J-band upper limit from WINTER
  16. Fermi trigger No 750788395: Global MASTER-Net observations report
  17. GRB 241017A: Swift ToO observations
  18. Fermi GRB 241016B: 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 240916A: radio detection with the VLA
  22. GRB241013A: REM observations
  23. Fermi GRB 241013B: Global MASTER-Net observations report
  24. Integral GRB241013.04: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  26. GRB 241009A: GRANDMA optical upper limits
  27. GRB 241009A: Swift-XRT afterglow detection
  28. GRB 241010A: JinShan optical observations and potential host galaxy
  29. GRB 241006A: ATCA Radio Upper Limits
  30. Fermi trigger No 750211959: Global MASTER-Net observations report
  31. Swift GRB 241010A: Global MASTER-Net observations report
  32. Fermi trigger No 750291012: Global MASTER-Net observations report
  33. GRB 241010A: J-band observations with WINTER
  34. Fermi GRB 241010B: Global MASTER-Net observations report
  35. GRB 241010A: LCO optical observations
  36. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  37. GRB 241009A: Swift ToO observations
  38. GRB 241002B: Swift-XRT afterglow detection
  39. GRB 241002A: NOT optical upper limits
  40. Fermi GRB 241008A: Global MASTER-Net observations report
  41. IceCube-241006A: No candidates from the Zwicky Transient Facility
  42. GRB 241006A: GRANDMA optical upper limits
  43. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  44. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  45. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  46. GRB 240910A: LBT optical observations
  47. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  48. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  49. GRB 241006A: PRIME near-infrared upper limits
  50. GRB 241006A: Swift/UVOT Upper Limits
  51. GRB 241006A: SVOM/VT follow-up and optical upper limit
  52. IceCube Alert 241006.94: Global MASTER-Net observations report
  53. GRB 241001A: Swift-XRT afterglow detection
  54. Swift GRB241006.91: Global MASTER-Net observations report
  55. Fermi trigger No 749721670: Global MASTER-Net observations report
  56. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  57. GRB 241002B: Fermi GBM Observation
  58. Fermi trigger No 749735279: Global MASTER-Net observations report
  59. Fermi trigger No 749630753: Global MASTER-Net observations report
  60. Fermi trigger No 749693019: Global MASTER-Net observations report
  61. GRB 241002B: Swift-XRT observations
  62. GRB 241002B: Swift ToO observations
  63. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  64. GRB 241002B: PRIME near-infrared detection
  65. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  66. GRB 241002C: Swift ToO observations
  67. GRB 241001A : SVOM/VT optical detection
  68. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  69. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  70. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  71. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  72. GRB241001A: REM optical/NIR upper limits
  73. GRB 241002A: Swift/UVOT Upper Limits
  74. EP240930a: Liverpool Telescope observations
  75. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  76. GRB 241001A: Swift/UVOT Detection
  77. GRB 241001A: VLT/X-shooter redshift
  78. GRB 241002B: GOTO optical counterpart candidate
  79. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  80. GRB 240929A: Liverpool Telescope prompt followup observations
  81. Fermi GRB 241002B: Global MASTER-Net observations report
  82. GRB 241001A: Swift-XRT observations
  83. GRB241001A: optical afterglow candidate
  84. GRB 241002A: 1.5m OSN optical upper limit
  85. GRB 241001A: Swift ToO observations
  86. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  87. EP240930a: GOTO optical upper limits
  88. EP EP240930a: Global MASTER-Net observations report
  89. EP240930a: EP-WXT detection of a fast X-ray transient
  90. AMON NuEM 240926A: Swift XRT Follow-up
  91. GRB 240929A : Leavitt Observatory optical upper limit
  92. Fermi GRB 240930B: Global MASTER-Net observations report
  93. GRB 240825A: LBT optical observations
  94. Fermi GRB 240930A: Global MASTER-Net observations report
  95. Fermi trigger No 749339671: Global MASTER-Net observations report
  96. Fermi GRB 240929A: Global MASTER-Net observations report
  97. Integral GRB240929.83: Global MASTER-Net observations report
  98. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  99. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  100. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A

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