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"

23693 results found.

  1. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  2. GRB 260104A: Swift-XRT refined Analysis
  3. GRB 260104A: Enhanced Swift-XRT position
  4. GRB 260104A: Swift detection of a burst
  5. GRB 260101A: COLIBRÍ optical observations
  6. GRB 260102A: Swift-XRT observations
  7. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  8. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  9. EP260101a: Einstein Probe detection of an X-ray transient
  10. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  11. GRB 260101A: LCO detection of the optical counterpart
  12. GRB 260101A: Swift detection of a burst with an optical counterpart
  13. GRB 251230A: GRANDMA/TAROT Early Detection
  14. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  15. EP251229a: Optical upper limit with Kinder observations
  16. GRB 251230A: 1.3m DFOT optical upper limit
  17. GRB 251230A: Swift-XRT refined Analysis
  18. GRB 251230A: Swift/UVOT detection
  19. EP251229a: BOOTES-2 early optical upper limit
  20. GRB 251230A: GOTO optical upper limit
  21. GRB 251230A: Early optical counterpart detection by LCO.
  22. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  23. GRB 251226A: Glowbug gamma-ray detection
  24. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  25. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  26. GRB 251222A: NUTTelA-TAO Early Measurements
  27. GRB 251222A/EP251222b: Optical detection with Kinder observations
  28. EP251222a: Optical upper limit with Kinder observations
  29. GRB 251221A: Swift-BAT refined analysis
  30. GRB 251205A: Kilonova-Catcher optical afterglow detection
  31. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  32. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  33. EP251221a: PRIME upper limit
  34. Konus-Wind detection of GRB 251222A / EP251222b
  35. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  36. EP251222a: NTT/ULTRACAM optical observations
  37. EP251222a: GOTO optical upper limit
  38. GRB 251222A / EP251222b: GOTO optical counterpart detection
  39. EP251222a: GSP Optical Counterpart Detection
  40. GRB 251222A: PRIME near-infrared detection
  41. GRB 251222A: NOT optical observations
  42. IPN triangulation of GRB 251220B (short)
  43. GRB 251222A: SVOM/VT optical candidate
  44. EP251220a: PRIME upper limit
  45. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  46. GRB 251221A: PRIME near-infrared observation
  47. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  48. EP 251220a: GOTO optical counterpart detection
  49. GRB 251221A: COLIBRÍ detection of the optical counterpart
  50. EP 251220a: COLIBRÍ detection of the optical counterpart
  51. GRB 251221A: Swift detection of a burst
  52. GRB 251220A: MAXI/GSC detection
  53. IceCube-251218A: COLIBRÍ optical upper limits
  54. GRB 251215A: Swift/UVOT Upper LImits
  55. GRB 251215A: COLIBRÍ optical upper limit
  56. EP251214b: KAIT optical upper limit
  57. GRB 251215A: Swift-XRT observations
  58. EP251214a: Optical upper limit with Kinder observations
  59. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  60. GRB 251215A: Glowbug gamma-ray detection
  61. GRB 251214B: VLT/X-shooter observations
  62. GRB 251214B: Swift-BAT refined analysis
  63. GRB 251202A: radio detection with the VLA
  64. GRB 251214B: AbAO optical observations
  65. GRB 251214B: LCO detection of the optical counterpart
  66. GRB 251209A: GECAM-B observation of a long burst
  67. GRB 251214B: Fermi GBM Observation
  68. GRB 251209A: Insight-HXMT/HE detection
  69. EP251214a: KAIT optical upper limit
  70. GRB 251214D: AstroSat CZTI detection of a long burst
  71. GRB 251213A: AstroSat CZTI detection
  72. GRB 251214A: AstroSat CZTI detection
  73. GRB 251214B: COLIBRÍ observations of the afterglow
  74. EP251214a: COLIBRÍ optical upper limit
  75. EP251214.305: COLIBRÍ optical upper limit
  76. GRB 251214B: Swift detection of a burst with an optical counterpart
  77. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  78. EP251212a: KAIT optical upper limit
  79. EP251212a / GRB 251212A: AstroSat CZTI detection
  80. GRB 251211B: AstroSat CZTI detection
  81. EP251212a : COLIBRÍ optical upper limit
  82. IceCube-251210A: DDOTI Optical Upper Limit
  83. GRB 251209A: AstroSat CZTI detection
  84. GRB 251208A: AstroSat CZTI detection
  85. GRB 251208A: Glowbug gamma-ray detection
  86. GRB 251208B: COLIBRÍ optical upper limits
  87. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  88. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  89. GRB 251208B: Swift-XRT afterglow detection
  90. GRB 251208D: LAST optical upper limit
  91. GRB 251205A: J-band detection with WINTER
  92. GRB 251208D: Swift-XRT observations
  93. GRB 251208B: Fermi-LAT detection
  94. GRB 251206A: SVOM detection of a burst through offline search
  95. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  96. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  97. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  98. GRB 251205A: ZTF and ATLAS optical afterglow detections
  99. GRB 251205A: Swift-BAT refined analysis
  100. GRB 251205A: Swift-XRT refined Analysis

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