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"

10956 results found.

  1. GRB 250702F: GRANDMA observations
  2. IceCube-250706A: COLIBRÍ optical upper limits
  3. GRB 250706B: SVOM/VT optical observation
  4. GRB 250703A: EIRSAT-1 GMOD Detection
  5. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  6. GRB 250704A: SVOM/VT optical observation
  7. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  8. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  9. GRB 250704A: SVOM detection of a burst
  10. GRB 250702F: Swift/UVOT Detection
  11. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  12. GRB 250702F: Fermi GBM Observation
  13. GRB 250424A: VIRT Optical Upper Limit
  14. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  15. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  16. GRB 250702F: COLIBRÍ Observations of the Afterglow
  17. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  18. GRB 250702F: NOT observations of the optical afterglow
  19. GRB 250702F: Swift detection of a burst with an optical counterpart
  20. GRB 250628B: SVOM/VT optical upper limit
  21. GRB 250628A: VLT/X-shooter upper limits
  22. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  23. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  24. GRB 250625A: Fermi-LAT detection
  25. GRB 250617B: Mondy and SAO RAS optical observations on 2025-06-23, 2025-06-24
  26. GRB 241018A: Maidanak optical observations
  27. sb25061207/GRB 250612D - SVOM/ECLAIRs refined analysis
  28. GRB 250521A: VZLUSAT-2 detection
  29. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  30. GRB 250617B: Assy AZT-20 Optical Observations
  31. SVOM sb25061207: AbAO AS-32 Optical Upper Limit
  32. sb25061207: EP-FXT follow-up observation and afterglow candidate
  33. EP250612a / GRB 250612B: SVOM/VT optical candidate
  34. sb25061218: SVOM detection of a X-ray transient
  35. sb25061207: SVOM/VT optical counterpart
  36. sb25061207: SVOM detection of a X-ray transient
  37. GRB 250610B: SVOM/VT optical shallow decay
  38. GRB 250610B: SVOM/GRM analysis
  39. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  40. GRB 250610B: SVOM/VT optical counterpart
  41. GRB 250610B: SVOM detection of a long burst
  42. EP250610a: SVOM/VT optical upper limit
  43. GRBAlpha reentry on June 9, 2025
  44. The EP-WXT trigger 01709178283 is likely a flaring star
  45. GRB 250527C: CrAO Optical Upper Limit
  46. GRB 250605A: SVOM/VT optical upper limit
  47. GRB 250605A: Swift detection of a burst
  48. GRB 250601A: PRIME H band upper limit.
  49. GRB 250601A: PRIME J band upper limit.
  50. GRB 250602A: Fermi-LAT detection
  51. GRB 250530A: VLT/HAWK-I NIR counterpart fading
  52. EP#01709177494: SVOM/VT optical observations
  53. GRB 250530A: SVOM/VT optical upper limit
  54. GRB 250527D: CALET Gamma-Ray Burst Monitor detection
  55. GRB 250527C: Swift/UVOT Upper Limits
  56. GRB 250521C (short): Zwicky Transient Facility identification of a possible fast optical transient counterpart
  57. EP250526a: SVOM/VT optical upper limit
  58. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  59. GRB 250521A: GRBAlpha detection
  60. GRB 250520A: GRBAlpha detection
  61. The EP-WXT trigger 01709176612: SVOM/VT optical observations
  62. GRB 250521B: EP-FXT follow-up observation and afterglow candidates
  63. GRB 250521D: SVOM/VT optical observations
  64. GRB 250520A: CALET Gamma-Ray Burst Monitor detection
  65. GRB 250521B: SVOM detection of a burst through offline search
  66. IPN triangulation of GRB 250516B
  67. GRB 250520A：SVOM/VT optical candidate
  68. GRB 250516B: GRBAlpha detection
  69. GRB 250520A: Swift detection of a burst
  70. GRB 250515A: NOT classification of GOTO25cqo as a type-Ia SN
  71. GRB 250515A/GOTO25cqo: SVOM/VT optical blue color
  72. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  73. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  74. GRB 250512B/EP250512a: SVOM/VT optical fading
  75. GRB 250512B/EP250512a：SVOM/VT bright optical counterpart
  76. GRB 250507B: GRBAlpha detection
  77. GRB 250506A: GRBAlpha detection
  78. EP250511a: SVOM/VT optical candidate comfirmation
  79. EP250508a: SVOM/VT optical candidate fading
  80. GRB 250506A: NOT optical upper limits
  81. EP250508a: SVOM/VT optical candidate
  82. GRB 250506A: SVOM/VT optical upper limit
  83. GRB 250506A: Swift/UVOT Upper Limits
  84. GRB 250427B : SVOM detection of a burst through offline search
  85. GRB 250507A: SVOM/VT optical upper limit
  86. GRB 250504A: VLT/X-shooter upper limits
  87. GRB 250504A: SVOM/VT upper limit
  88. GRB 250502A: Mondy and Tien-Shan Optical Observations
  89. GRB 250502A: Montarrenti Observatory optical detection
  90. GRB 250502A: NOT optical observations
  91. GRB 250502A: Redshift from OSIRIS+/GTC z = 2.163
  92. GRB 250407A: VZLUSAT-2 detection
  93. GRB 250430A : MITSuME Akeno optical upper limits
  94. GRB 250430A / EP250430a: VLT/X-shooter spectroscopic redshift z = 0.767
  95. GRB 250424A: CALET Gamma-Ray Burst Monitor detection
  96. GRB 250430A: Swift detection of a burst with optical counterpart
  97. EP250427a: Lesedi optical counterpart detection
  98. EP250427a / GRB 250427A: VLT/X-shooter redshift confirmation z = 1.520
  99. GRB 250424A: PRIME near-infrared detection
  100. GRB 250419A: Mondy 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