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"

28248 results found.

  1. GRB 250721A: Swift-XRT observations
  2. GRB 250717B: SVOM/GRM observation
  3. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  4. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  5. GRB 250721A: MAXI/GSC detection
  6. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  7. GRB 250717B: COLIBRÍ optical upper limit
  8. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  9. GRB 250717B: Swift-XRT observations
  10. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  11. Swift GRB250718.01: Global MASTER-Net observations report
  12. GRB 270713A: Kitab and AbAO Optical Observations
  13. GRB 250717B: Fermi GBM Observation
  14. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  15. GRB 250716A: Swift-XRT afterglow detection
  16. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  17. GRB 250716A: Fermi GBM Observation
  18. GRB 250714A: SVOM/GRM observation
  19. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  20. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  21. GRB 250713A: Mephisto optical upper limits
  22. GRB 250713A: SVOM/VT optical upper limit
  23. GRB 250713A: NOT optical upper limits
  24. GRB 250713A: OHP/T193 upper limit
  25. GRB 250713A: SVOM/C-GFT upper limit
  26. GRB 250706B/C: 7DT Follow-up Observations
  27. GRB 250713A: Swift-XRT observations
  28. GRB 250713A: EP-FXT counterpart detection
  29. EP250711a: COLIBRÍ continuous optical observations
  30. GRB 250706A: Swift-BAT refined analysis
  31. GRB 250702F: Swift-BAT refined analysis
  32. GRB 250628A: Swift-BAT refined analysis
  33. LIGO/Virgo/KAGRA S250712cd: Updated Sky localization
  34. GRB 250713A: JinShan optical upper limits
  35. GRB 250713A: SVOM detection of a long burst
  36. EP250711a: Global MASTER-Net observations report
  37. GRB 250711A: DDOTI Optical Upper Limit
  38. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  39. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  40. GRB 250711A: SVOM/GRM observation
  41. EP250711a: NOT optical counterpart candidate
  42. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  43. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  44. GRB 250704A: GRANDMA observations
  45. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  46. LIGO/Virgo/KAGRA S250711q: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  49. IceCube-250708A: No Candidates from WINTER
  50. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  51. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  52. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  53. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  54. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  55. EP250704a/GRB 250704B: 10 GHz VLA detection
  56. LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
  57. IceCube-250706A: No Candidates from WINTER
  58. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  59. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  60. LIGO/Virgo/KAGRA S250705cb: Updated Sky localization
  61. LIGO/Virgo/KAGRA S250704ab: Updated Sky localization and EM Bright Classification
  62. LIGO/Virgo/KAGRA S250702n: Updated Sky localization
  63. LIGO/Virgo/KAGRA S250701bq: Updated Sky localization
  64. EP250704a/GRB250704B : HCT optical and NIR upper limits
  65. LIGO/Virgo/KAGRA S250701bp: Updated Sky localization
  66. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  67. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  68. GRB 250702F: radio detection with the VLA
  69. IceCube-250706A: EP-FXT follow-up observations
  70. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  71. GRB 250706B/C: Fermi-LAT detection
  72. IceCube-250706A: Global MASTER-Net observations report
  73. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  74. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  75. GRB 250706B: Swift/UVOT Detection
  76. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  77. GRB 250702F: GRANDMA observations
  78. GRB 250706A: Swift-XRT refined Analysis
  79. GRB 250706B: refined SVOM/MXT data analysis
  80. GRB 250706A: Swift/UVOT Upper Limits
  81. GRB 250706B: REM optical observations
  82. GRB 250706A: REM optical/NIR observations
  83. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  84. IceCube-250416A: DDOTI Optical Upper Limit
  85. IceCube-250706A: COLIBRÍ optical upper limits
  86. GRB 250706A: JinShan optical upper limits
  87. GRB 250706A: SAO RAS optical observations
  88. EP250704A: NOWT Detection
  89. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  90. GRB250706B: Swift-XRT counterpart detection
  91. GRB 250706B: iTelescope optical observations
  92. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  93. GRB 250706B: SVOM/VT optical observation
  94. GRB 250706B: TRT bright optical counterpart detection
  95. GRB 250706A: GROWTH-India Telescope optical upper limit
  96. GRB 250706B: SVOM detection of a long burst
  97. GRB 250706A: Swift detection of a burst
  98. GRB 250704B: Swift-XRT refined Analysis
  99. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  100. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart

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