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"

45688 results found.

  1. Konus-Wind detection of GRB 250306A
  2. GRB 250307A: Fermi GBM Final Real-time Localization
  3. GRB 250306A: Swift-BAT refined analysis
  4. GRB 250306A: NuSTAR detection of the prompt emission
  5. EP250304a: MeerKAT detection of a possible radio counterpart
  6. IceCube-241016A: MASTER flaring blazar 5BZU J073038.29-320820.2 with Zhirkov effect
  7. GRB 250305A: AstroSat CZTI detection
  8. EP250302a:Xinglong optical observations
  9. GRB 250306A: AstroSat CZTI detection
  10. Fermi trigger No 762963055: Global MASTER-Net observations report
  11. Fermi Gamma-ray Burst Monitor trigger 762963055/250306591 is not a GRB
  12. Swift GRB 250306A: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S250207bg: Update-5 NED Galaxies in the Localization Volume
  14. GRB 250306A: Swift detection of a burst
  15. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  16. GRB250101A: Radio upper limits from VLA observations
  17. LIGO/Virgo/KAGRA S250306ej: Retraction of GW compact binary merger candidate
  18. GRB 250305A: SVOM/GRM observation of a burst
  19. The EP-WXT trigger 01709132323 is likely a flaring star
  20. EP250304A: Upper limits from Fermi-GBM Observations
  21. Fermi GRB 250305A: Global MASTER-Net observations report
  22. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  23. GRB 250305A: Fermi GBM Final Real-time Localization
  24. EP250302a: Optical Observations at CrAO and SAO RAS
  25. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  26. EP 250304A: Optical counterpart detection by LCO
  27. EP250302A: 1.3m DFOT optical afterglow detection
  28. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  29. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  30. Konus-Wind detection of GRB 250222A
  31. EP250304a: REM NIR upper limits
  32. IPN triangulation of GRB 250222A
  33. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  34. EP250302a: Mondy Continued Optical Observations
  35. EP250304a: VLT/X-shooter redshift z = 0.200
  36. EP250304a: Swift-XRT detection of a fading X-ray source
  37. EP250304a: TRT optical counterpart detection
  38. LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate
  39. EP250304a: Global MASTER-Net observations report
  40. EP250304a: Einstein Probe detection of an X-ray transient
  41. The EP-WXT trigger 01709132212 is not a real source
  42. EP250302a: SVOM/VT optical observation
  43. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
  44. EP250302a: SAO RAS optical observations
  45. EP250302a : GIT optical follow-up
  46. EP250302a: VLT/X-shooter redshift confirmation
  47. EP250225a: the candidate optical counterpart is an AGN
  48. EP250302a: Kinder optical follow-up observations
  49. LIGO/Virgo/KAGRA S250302av: 2 counterpart neutrino candidate events from an IceCube neutrino search
  50. EP250302a: Swift/UVOT detection
  51. EP250302a: NUTTelA-TAO Early Measurments
  52. EP250302a: optical observation from the INAF Asiago Observatory
  53. EP250302a: REM NIR upper limits
  54. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  55. EP250302a: Mondy Observations and Optical Light Curve
  56. EP250302a: VLT/MUSE optical redshift z = 1.131
  57. INTEGRAL: end of scientific operations
  58. EP250302A: VLT near-infrared observations
  59. EP250302A: VLT/X-shooter tentative redshift
  60. EP250302a: OHP/T193 optical and spectroscopic observations
  61. EP250302a: Global MASTER-Net observations report
  62. EP250302a: Xinglong F60B optical observation
  63. EP250302a: Swift-XRT observations of a fading X-ray source
  64. EP250302a: Einstein Probe detection of an X-ray transient
  65. EP250302a: SVOM/C-GFT optical observations
  66. GRB 250226A: GRANDMA Optical Observations
  67. EP250302a: Montarrenti Observatory optical detection
  68. Fermi GRB 250302A: Global MASTER-Net observations report
  69. EP250302a: FTW optical and NIR detection
  70. EP250302a: Nanshan/HMT optical counterpart detection
  71. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  72. GRB 250302A: Fermi GBM Final Real-time Localization
  73. GRB 250228A: Fermi GBM Final Localization
  74. The EP-WXT trigger 01709132140 is likely a flaring star
  75. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  76. GRB 250225B: VLT near-infrared afterglow confirmation
  77. EP250228a: Optical observations with Kinder and Swift/UVOT
  78. Konus-Wind detection of GRB 250226A
  79. GRB 250225B: EIRSAT-1 GMOD Detection
  80. GRB 250226A: KAO Optical Upper Limit
  81. GRB 250226A: AbAO AS-32 Optical Upper Limit
  82. EP250227a: Global MASTER-Net observations report
  83. EP250223A: Upper limits from Fermi-GBM Observations
  84. EP250227a: TRT optical upper limit
  85. GRB 250225B: VLT/HAWKI near-infrared observations
  86. EP250227a: Optical upper limits with Kinder observations
  87. EP250227a: NOT optical observations
  88. EP250227a: Einstein Probe detected of a fast X-ray transient
  89. EP250228a: updates on the EP observations
  90. GRB 250226A: Fermi GBM Observation
  91. EP250225a: EP-FXT follow-up observation
  92. EP250223a: J band upper limit by SYSU 80cm telescope
  93. EP250228a: Swift/XRT localisation
  94. EP250228a: Global MASTER-Net observations report
  95. EP250228a: Einstein Probe detection of an X-ray transient
  96. GRB 250226A / EP250226a: LCO detection of the afterglow
  97. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  98. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  99. GRB 250225B: VLT/Xshooter imaging
  100. GRB 250205A / EP250205A: further radio observations with the VLA

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