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"

22208 results found.

  1. GRB 250129a: Liverpool Telescope optical follow-up
  2. GRB 240129A: further SAO RAS optical observations
  3. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  4. GRB 250129A: SVOM/C-GFT optical observations
  5. Swift GRB250129A: MASTER 4 days observations report
  6. GRB 250201A: INTEGRAL SPI/ACS detection
  7. GRB 250129A: 1.3m DFOT Optical observations
  8. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  9. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  10. GRB 250129A: Skynet Continued Optical Observations
  11. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  12. GRB 250129A: SAO RAS optical observations
  13. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  14. GRB 250129A: optical photometry from Konkoly
  15. GRB 250129A: COLIBRÍ Optical Observations
  16. GRB 250128B: VLA possible radio detection
  17. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  18. GRB 250129A: NOT optical observations of continuining activity
  19. GRB 250129a: Liverpool Telescope optical follow-up
  20. GRB 250129A: TNG NIR afterglow detection
  21. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  22. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  23. GRB 250128B: VLA radio upper limit
  24. Ep250125A: 1.3m DFOT optical upper limit
  25. GRB 250129A: Skynet optical observations
  26. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  27. GRB 250128B: Gemini-North optical extended source detection
  28. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  29. GRB 250129A: Swift/UVOT Detection
  30. GRB 250128B: VLT/HAWKI near-infrared observations
  31. GRB 250127A: CrAO and Terskol optical upper limits
  32. GRB 250128B: VLT/FORS2 optical observations
  33. GRB 250129A: REM optical/NIR afterglow detection
  34. GRB 250129A: OHP/T193 optical and spectroscopy observations
  35. GRB 250129A: Early afterglow detection by LCO.
  36. GRB 250129A: LCO optical observations
  37. GRB 250129A: NOT optical observations and redshift confirmation
  38. GRB 250129A: GOTO optical observations show brightening afterglow
  39. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  40. Swift GRB 250129A: Global MASTER-Net observations report
  41. Fermi GRB 250128B: Global MASTER-Net observations report
  42. GRB 250128B: GOTO optical upper limit
  43. Swift GRB 250128B: Global MASTER-Net observations report
  44. EP250125a: Upper limits from Swift/BAT-GUANO
  45. GRB 250128B: LCO optical observations
  46. GRB 250127A: Swift-XRT observations
  47. GRB 250127B: DDOTI Upper Limit on the Afterglow
  48. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  49. Fermi GRB 250128A: Global MASTER-Net observations report
  50. Fermi GRB 250127B: Global MASTER-Net observations report
  51. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  52. GRB 250127A: SVOM/VT upper limit
  53. GRB 250127A: Swift ToO observations
  54. GRB 250127A: LCO optical upper limit
  55. EP250125A: Non-detection from Fermi-GBM Observations
  56. EP250125a: Optical upper limit with Kinder observations
  57. EP250125a: REM optical counterpart detection
  58. EP250125a: Swift/XRT detection of a fading counterpart
  59. EP250125a: a new X-ray transient detected by Einstein Probe
  60. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  61. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  62. EP250108a: AbAO, CMO and Terskol optical upper limits
  63. Konus-Wind detection of GRB 250119B
  64. GRB 250121A: INTEGRAL/SPI-ACS detection
  65. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  66. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  67. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  68. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  69. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  70. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  71. ATCA detection of possible radio counterpart to GRB 250114A
  72. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  73. GRB 250119B: INTEGRAL/SPI-ACS detection
  74. EP 250108A: Late-time optical observation by LCO
  75. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  76. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  77. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  78. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  79. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  80. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  81. GRB 250117A: GECAM observation of a short burst
  82. EP250108a / AT2025kg: GMG Optical Observations
  83. EP250108a / AT2025kg: VLA radio upper limit
  84. GRB 241217A / EP241217B: radio detection with the VLA
  85. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  86. GRB 250114B: Swift-XRT afterglow detection
  87. GRB 250114B: SVOM/VT upper limit
  88. EP250108a: MeerKAT radio upper limit
  89. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  90. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  91. Konus-Wind detection of GRB 250113A
  92. GRB 250114B: Liverpool Telescope optical upper limit
  93. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  94. GRB 250114B: Swift-XRT observations
  95. GRB 250114A: LCO optical counterpart detection.
  96. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  97. Integral GRB250114.55: Global MASTER-Net observations report
  98. GRB 250114A: LCOGT optical afterglow i-band detection
  99. GRB 250114B: Swift ToO observations
  100. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the 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