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"

21049 results found.

  1. SVOM GRB251129A: Global MASTER-Net observations report
  2. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  3. Fermi GRB 251128A: Global MASTER-Net observations report
  4. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  5. GRB 251126A: further SAO RAS optical observations
  6. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  7. GRB 251126A NUTTelA-TAO Early Measurements
  8. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  9. GRB251126A: MAO/AZT-22 optical observations
  10. GRB251126A: Continued optical observation from 1.3m DFOT
  11. GRB 251126A: Swift/UVOT Detection
  12. GRB 251126A: Mondy and SAO RAS optical observations
  13. GRB 251126A: NOT optical observations
  14. GRB 251126A: 1.3m DFOT optical afterglow detection
  15. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  16. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  17. Fermi GRB 251127A: Global MASTER-Net observations report
  18. GRB 251126A: Kilonova-Catcher optical afterglow detection
  19. GRB 251126A: Asiago i-band detection
  20. GRB 251126A: Nanshan/HMT optical afterglow detection
  21. Swift GRB 251126A: Global MASTER-Net observations report
  22. GRB 251126A: GIT discovery of the likely optical afterglow
  23. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  24. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  25. EP251124b: NOT r- and z-band optical upper limits
  26. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  27. Fermi GRB 251125B: Global MASTER-Net observations report
  28. EP251124b: Global MASTER-Net observations report
  29. Fermi GRB 251125A: Global MASTER-Net observations report
  30. EP251124a: NOT r- and z-band optical upper limits
  31. EP251124a: Global MASTER-Net observations report
  32. EP251124a: Swift-XRT observations
  33. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  34. EP251124a: Optical upper limit with Kinder observations
  35. EP251118A: 6 GHz VLA Detection
  36. Fermi GRB 251124a: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  38. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  39. GRB 251116C: Swift-XRT confirmation of fading
  40. GRB 251122A/EP251122a: FTW optical and NIR observations
  41. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  42. EP251118A: 3.6m DOT optical afterglow detection
  43. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  44. GRB 251122A / EP251122a: WFST optical observations
  45. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  46. GRB 251122A / EP251122a: LCO optical upper limits
  47. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  48. EP251122a: Global MASTER-Net observations report
  49. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  50. EP251118a: Continued Optical Detection with Kinder observations
  51. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  52. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  53. EP251118a: Xinglong-2.16m optical observation
  54. Fermi trigger No 785388351: Global MASTER-Net observations report
  55. EP251118A: 1.3m DFOT optical afterglow detection
  56. GRB 251118A: Swift/UVOT Detection
  57. EP251118a / GRB 251118C: SAO RAS optical observations
  58. GRB 251118A: Swift-XRT afterglow detection
  59. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  60. EP251118a: Optical detection with Kinder observations
  61. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  62. EP251118a / GRB 251118C: SVOM/VT optical observation
  63. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  64. GRB 251116C: NOT optical observations
  65. GRB 251117A: Swift-XRT observations
  66. EP251118A / GRB 251118C : MASTER optical counterpart observations
  67. EP251118a: FTW optical and NIR observations
  68. EP251118a: VLT near-infrared observation
  69. EP251118a: GOTO optical afterglow detection
  70. EP251118a: Global MASTER-Net observations report
  71. LAT GRB251118.86: Global MASTER-Net observations report
  72. EP251118a: NOT candidate optical counterpart
  73. GRB 251118A: Swift ToO observations
  74. EP251118a: Einstein Probe detected of a fast X-ray transient
  75. Fermi GRB 251118B: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  77. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  78. GRB 251116C: SVOM/ECLAIRs refined analysis
  79. GRB 251116B: SVOM/ECLAIRs refined analysis
  80. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  81. GRB 251115A: Swift-XRT observations
  82. GRB 251117A: Tiled Swift observations
  83. LAT GRB251117.51: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  85. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  86. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  87. GRB 251116C: Swift-XRT observations
  88. EP251023a: Assy AZT-20 optical observations
  89. EP251023a: UAFO and AbAO optical observations
  90. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  91. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  92. GRB 251025B: further Mondy optical observations
  93. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  94. SVOM GRB251116C: Global MASTER-Net observations report
  95. GRB 251116B: SVOM detection of a burst
  96. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  97. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  98. GRB 251115A: Tiled Swift observations
  99. Fermi GRB 251115A: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume

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