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.

"N/A_MC170219_R1" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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"

10934 results found.

  1. EP250821a: SVOM/VT optical observation
  2. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  3. LIGO/Virgo/KAGRA S250818k: WFST pre-discovery limits and follow-up observations of AT 2025ulz
  4. LIGO/Virgo/KAGRA S250818k: Multi-band Gemini GMOS Detections
  5. LIGO/Virgo/KAGRA S250818k: ATLAS pre-discovery limits for AT2025ulz
  6. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  7. GRB 250818B: Keck redshift of the optical afterglow
  8. LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations
  9. GRB 250818B: SVOM/VT optical observation
  10. GRB 250813B: Liverpool Telescope optical upper limits
  11. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  12. GRB 250812A: SVOM/VT optical continued observation
  13. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  14. LIGO/Virgo/KAGRA S250813k: Swift XRT observations, 2 X-ray sources
  15. GRB 250813B: SVOM/VT optical observations
  16. GRB 250813B: VLT X-shooter spectroscopic redshift z = 1.752
  17. GRB 250812A: NTT spectroscopic redshift z = 2.57
  18. EP250812a: NOT, NTT, and GS observations
  19. EP250812a: SVOM/VT optical counterpart
  20. GRB 250807B: Swift-BAT refined analysis
  21. GRB 250812A: SVOM/VT optical afterglow confirmation
  22. GRB 250807A: Swift-BAT refined analysis
  23. GRB 250807B: SVOM/VT optical observation
  24. GRB 250808A: VLT X-shooter candidate counterpart
  25. GRB 250807A: SVOM/VT optical continued observation
  26. GRB 250808A: SVOM detection of a long burst
  27. GRB 250807B: Swift/UVOT Detection
  28. GRB 250807A: Swift/UVOT Detection
  29. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  30. GRB 250806A: SVOM/ECLAIRs refined analysis
  31. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  32. GRB 250807A: SVOM/GRM observation
  33. GRB 250807A: AstroSat CZTI detection of bright long burst
  34. GRB 250807B: NTT optical observations
  35. GRB 250807A: SVOM/VT optical observation
  36. GRB 250807B: Swift detection of a burst with an optical counterpart.
  37. EP250806a:SVOM/VT refined analysis
  38. EP250806a: Liverpool telescope optical upper limit
  39. GRB 250807A: Swift detection of a burst with an optical counterpart
  40. GRB 250806A: EP-FXT observation
  41. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  42. EP250806a: SVOM /VT optical candidate
  43. GRB 250806A: SVOM/VT refined analysis
  44. GRB 250805A: SVOM/VT optical counterpart
  45. GRB 250805A: ESO/VLT observations
  46. EP250802a: additional Liverpool Telescope upper limits
  47. EP250730a: SVOM/VT optical upper limit
  48. GRB 250702B: SMA observations
  49. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  50. EP250711a: CrAO and Assy optical observations
  51. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  52. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  53. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  54. GRB 250725A: PRIME near-infrared observations
  55. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  56. GRB 250727A: SVOM/ECLAIRs refined analysis
  57. GRB250727A: SVOM/VT optical upper limit
  58. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  59. GRB 250725A: SVOM/VT optical candidate
  60. GRB 250725A: Swift detection of a burst
  61. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  62. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  63. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  64. GRB 250721A: MAXI/GSC detection
  65. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  66. GRB 270713A: Kitab and AbAO Optical Observations
  67. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  68. GRB 250713A: SVOM/VT optical upper limit
  69. GRB 250713A: NOT optical upper limits
  70. GRB 250702F: Swift-BAT refined analysis
  71. GRB 250704A: GRANDMA observations
  72. GRB 250704A: SVOM/ECLAIRs refined analysis
  73. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  74. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  75. GRB 250702F: radio detection with the VLA
  76. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  77. GRB 250706B/C: Fermi-LAT detection
  78. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  79. GRB 250702F: GRANDMA observations
  80. IceCube-250706A: COLIBRÍ optical upper limits
  81. GRB 250706B: SVOM/VT optical observation
  82. GRB 250703A: EIRSAT-1 GMOD Detection
  83. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  84. GRB 250704A: SVOM/VT optical observation
  85. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  86. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  87. GRB 250704A: SVOM detection of a burst
  88. GRB 250702F: Swift/UVOT Detection
  89. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  90. GRB 250702F: Fermi GBM Observation
  91. GRB 250424A: VIRT Optical Upper Limit
  92. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  93. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  94. GRB 250702F: COLIBRÍ Observations of the Afterglow
  95. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  96. GRB 250702F: NOT observations of the optical afterglow
  97. GRB 250702F: Swift detection of a burst with an optical counterpart
  98. GRB 250628B: SVOM/VT optical upper limit
  99. GRB 250628A: VLT/X-shooter upper limits
  100. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations

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