Skip to main content
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"

3533 results found.

  1. IceCube Alert 250207.09: Global MASTER-Net observations report
  2. GRB 250204A: GRBAlpha detection
  3. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  4. GRB 250129A: Continued AbAO and Mondy optical observations
  5. EP250205a/GRB 250205A: Einstein Probe observation
  6. IPN triangulation of GRB 250204B (short/hard)
  7. GRB 250204A: Fermi GBM Final Real-time Localization
  8. Ep250125A: 1.3m DFOT optical upper limit
  9. GRB 250127A: CrAO and Terskol optical upper limits
  10. Fermi GRB 250128B: Global MASTER-Net observations report
  11. GRB 250128B: Fermi GBM Observation
  12. GRB 250128B: GOTO optical upper limit
  13. Swift GRB 250128B: Global MASTER-Net observations report
  14. GRB 250128B: LCO optical observations
  15. GRB 250128B: Fermi GBM Final Real-time Localization
  16. GRB 250127B: DDOTI Upper Limit on the Afterglow
  17. Fermi GRB 250128A: Global MASTER-Net observations report
  18. GRB 250128A: Fermi GBM Final Real-time Localization
  19. Fermi GRB 250127B: Global MASTER-Net observations report
  20. IPN triangulation of GRB 250119C
  21. GRB 250126A: MAXI/GSC detection
  22. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  24. Fermi trigger No 758442826: Global MASTER-Net observations report
  25. EP250111a: NOT likely optical counterpart
  26. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  27. EP250109a: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  29. GRB 241228B: Fermi-LAT detection
  30. Fermi GRB 250107B: Global MASTER-Net observations report
  31. Fermi trigger No 757753930: Global MASTER-Net observations report
  32. GRB 250103A: Swift-XRT observations
  33. GRB 250103A: Montarrenti Observatory optical detection
  34. GRB 250103A: Fermi GBM Observation
  35. GRB 250103A: Xinglong 2.16m Optical Candidate
  36. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  37. GRB 250103A: SVOM detection of a long burst
  38. GRB 250101A: Swift/UVOT Detection
  39. GRB 250101A: AKO Optical Afterglow Detection
  40. GRB 250101A : GIT optical detection
  41. GRB 250101A: GMG Optical Observation
  42. GRB 250101A: Swift detection of a burst with an optical counterpart
  43. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  44. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 241228B: Fermi GBM Observation
  46. GRB 241228A: Mondy optical afterglow observations
  47. Swift GRB 241229B: Global MASTER-Net observations report
  48. GRB 241229A: GOTO optical upper limits
  49. GRB 241228A: NOT optical upper limits
  50. GRB 241228B: LCO optical observation
  51. Fermi GRB 241228B: Global MASTER-Net observations report
  52. GRB 241228A: Fermi GBM Observation
  53. GRB241228B: GROWTH-India Telescope optical observations
  54. Swift GRB 241228A: Global MASTER-Net observations report
  55. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  56. GRB 241228B: GOTO24jmz optical follow-up observations
  57. GRB 241228B: TRT optical counterpart confirmation
  58. GRB 241228B: GOTO possible optical counterpart candidate
  59. GRB 241228B: Fermi GBM Final Real-time Localization
  60. Fermi GRB 241226A: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  62. Fermi trigger No 756678579: Global MASTER-Net observations report
  63. IceCube Alert 241224.30: Global MASTER-Net observations report
  64. GRB 241223A: GOTO optical observations summary
  65. Fermi trigger No 756447119: Global MASTER-Net observations report
  66. Fermi GRB 241221A: Global MASTER-Net observations report
  67. EP241217a: 1.6m Mephisto multi-band optical observations
  68. GRB 241217A/EP241217b: REM optical/NIR upper limits
  69. EP241217b: Global MASTER-Net observations report
  70. EP241217a: Global MASTER-Net observations report
  71. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  72. Fermi GRB 241209A: Global MASTER-Net observations report
  73. Fermi trigger No 755277791: Global MASTER-Net observations report
  74. Fermi GRB 241207A: Global MASTER-Net observations report
  75. Fermi GRB 241204A: Global MASTER-Net observations report
  76. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  77. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  78. EP241201a: Global MASTER-Net observations report
  79. EP241126a: 1.6m Mephisto Optical Upper Limits
  80. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  82. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  83. Swift GRB 241128A: Global MASTER-Net observations report
  84. GRB 241128A: LCO optical detection
  85. GRB 241128A: 1.5m OSN optical afterglow detection
  86. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  87. Fermi trigger No 754492985: Global MASTER-Net observations report
  88. The EP-WXT trigger 01709125191 is not a real source
  89. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  90. Swift GRB241127.91: Global MASTER-Net OT detection
  91. IceCube Alert 241127.59: Global MASTER-Net observations report
  92. GRB 241120A: Mondy and AbAO optical observations
  93. GRB 241112B: Mephisto further optical observations
  94. Fermi GRB 241118A: Global MASTER-Net observations report
  95. EP241115a: Global MASTER-Net observations report
  96. Fermi GRB 241114A: Global MASTER-Net observations report
  97. EP241113a: Global MASTER-Net observations report
  98. EP241113b: Global MASTER-Net observations report
  99. Fermi GRB 241112A: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations

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