Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

22105 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. Fermi trigger No 752083996: Global MASTER-Net observations report
  5. GRB 241030A: SAO RAS optical observations
  6. EP241021a: AMI-LA radio detection
  7. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  8. GRB 241030B: Swift/UVOT Detection
  9. EP EP241030a: Global MASTER-Net observations report
  10. GRB 241029A: LCO optical detection
  11. Fermi trigger No 752006065: Global MASTER-Net observations report
  12. Swift GRB241030.77: Global MASTER-Net observations report
  13. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  14. GRB 241030B: SVOM/VT optical afterglow observations
  15. GRB 241030B: BTA observations
  16. GRB 241029A: SVOM/VT optical afterglow observations
  17. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  18. GRB 241030B: optical observations from the INAF Asiago Observatory
  19. GRB241030B: GRANDMA/TAROT Upper Limit
  20. GRB 241030B: SAO RAS optical observations
  21. GRB 241030B: Nanshan/HMT optical afterglow detection
  22. Konus-Wind detection of GRB 241030A
  23. GRB 240912A: radio detection with the VLA
  24. Fermi GRB 241030A: Global MASTER-Net observations report
  25. Swift GRB 241030A: Global MASTER-Net observations report
  26. GRB 241030A: Swift/UVOT Detection
  27. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  28. GRB 241030A: SVOM/C-GFT optical observations
  29. GRB 241026A: LBT optical observations
  30. EP241021a: Optical rebrightening observations with Mephisto
  31. GRB 241030A: Multiband optical detection with Mephisto
  32. GRB 241030A: SVOM/VT optical afterglow observations
  33. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  34. GRB 241030A: TRT optical observations
  35. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  36. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  37. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  38. GRB 241029A: SAO RAS optical observations
  39. GRB 241026A: SAO RAS optical observations
  40. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  41. EP241021a: SAO RAS observations of rebrightening
  42. EP241021a: ATCA radio observations
  43. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  44. GRB 241026A: Swift/UVOT Upper Limits
  45. GRB 241029A: Swift-XRT observations
  46. GRB 241029A: GOTO optical afterglow detection
  47. EP241021a: continued SOAR observations confirm optical rebrightening
  48. GRB 241029A: MASTER early optical counterpart detection
  49. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  50. GRB 241029A: Mephisto observations
  51. EP 241026b: LBT possible optical counterpart (brightening source)
  52. GRB 241029A: TRT optical afterglow candidate detection
  53. GRB 241029A: Swift ToO observations
  54. Fermi trigger No 751861204: Global MASTER-Net observations report
  55. GRB 240821A: Keck/LRIS spectroscopic observations
  56. Konus-Wind detection of GRB 241025A
  57. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  58. GRB 241026A: LBT redshift confirmation
  59. GRB 241025A: further SAO RAS optical observations
  60. GRB 241026A: BTA and Zeiss-1000 optical observations
  61. EP241026B: GROWTH-India Telescope optical upper limit
  62. GRB 241025A: Swift/UVOT Detection
  63. GRB 241026A: GROWTH-India Telescope optical observations
  64. GRB 241026A: J-band observations with WINTER
  65. GRB 241025A: SAO RAS optical observations
  66. GRB 241025A: Mondy optical observations
  67. EP241021a: SOAR observations of the optical counterpart
  68. EP241021a: further SAO RAS optical observations
  69. EP 241026b: LBT optical observations
  70. EP241021a: e-MERLIN radio observation
  71. EP EP241026b: Global MASTER-Net observations report
  72. GRB 241026A: KAIT optical observations
  73. EP241026b: EP detection of a fast X-ray transient
  74. Fermi trigger No 751616906: Global MASTER-Net observations report
  75. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  76. GRB 241026A: SAO RAS observations of possible optical afterglow
  77. Fermi GRB 241026A: Global MASTER-Net observations report
  78. Swift GRB241026.95: Global MASTER-Net observations report
  79. GRB241025A: 1.3m DFOT optical afterglow detection
  80. EP241021a: optical follow-up observations with Xinglong Observatory
  81. ​GRB 241025A: optical photometry from Konkoly
  82. GRB 241025A: GROWTH-India Telescope optical observations
  83. GRB 241025A: COLIBRÍ Detection of the Afterglow
  84. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  85. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  86. Fermi trigger No 751563375: Global MASTER-Net observations report
  87. Fermi trigger No 751554401: Global MASTER-Net observations report
  88. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  89. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  90. EP 241021a: Swift-XRT observations
  91. EP241021a: optical follow-up observations with the Liverpool Telescope
  92. Fermi GRB 241025A: Global MASTER-Net observations report
  93. Swift GRB 241025A: Global MASTER-Net observations report
  94. EP241025a (GRB 241025A): EP observations update
  95. GRB 241025A : SVOM/VT optical afterglow observations
  96. EP 241021A: Swift ToO observations
  97. EP241021a: Liverpool Telescope optical follow-up observations
  98. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  99. GRB 241025A: TRT optical afterglow observation
  100. Fermi GRB 241024B: Global MASTER-Net observations report

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