Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

11759 results found.

  1. Konus-Wind detection of GRB 250116A
  2. GRB 250116A: GECAM-B detection of a long burst
  3. GRB 250116A: Fermi-LAT detection
  4. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  5. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  6. Konus-Wind detection of GRB 250113A
  7. IPN triangulation of GRB 250113A
  8. GRB 250114A: Swift-XRT refined Analysis
  9. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  10. GRB 250114A: Swift detection of a burst with an optical counterpart
  11. GRB 250101A: Terskol Zeiss-2000 optical observations
  12. GRB 250106A: Swift-XRT afterglow detection
  13. Fermi trigger No 758442826: Global MASTER-Net observations report
  14. EP250108a / AT 2025kg: LCO optical observations
  15. EP250111a: Global MASTER-Net observations report
  16. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  17. EP250111a: a new X-ray transient detected by Einstein Probe
  18. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  19. Konus-Wind detection of GRB 250107C
  20. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  21. Konus-Wind detection of GRB 250107D (short/hard)
  22. IPN triangulation of GRB 250107D (short/hard)
  23. EP250109a: EP-WXT detection of an X-ray transient
  24. EP250108a: EP-WXT detection of an X-ray transient
  25. GRB 250108B: Swift-XRT refined Analysis
  26. Swift GRB 250108B: Global MASTER-Net observations report
  27. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  28. GRB 250103A: Swift-XRT afterglow detection
  29. GRB 250108B: Swift detection of a burst
  30. GRB 241228B: Fermi-LAT detection
  31. GRB 250101A: J band upper limit by SYSU 80cm telescope
  32. The EP-WXT trigger 01709129925 is likely a flaring star
  33. Fermi trigger No 757753930: Global MASTER-Net observations report
  34. GRB 250103B: Swift-XRT refined Analysis
  35. GRB 250103A: Bassano Bresciano Observatory upper limit
  36. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube Alert 250102.58: Global MASTER-Net observations report
  38. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  39. GRB 250103A: SVOM detection of a long burst
  40. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  41. GRB 250101A: further SAO RAS optical observations
  42. GRB 250101A: SAO RAS optical observations
  43. Swift GRB250101.56: Global MASTER-Net observations report
  44. GRB 241217a/EP241217b: ATCA Radio Detection
  45. EP241217a: VLA Radio Detection

  46. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  47. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  48. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  49. GRB 241229A: EP-FXT X-ray afterglow confirmation
  50. EP241217A: J band upper limit by SYSU 80cm telescope
  51. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  52. Konus-Wind detection of GRB 241228A
  53. EP240702a: 7DT Optical upper limits
  54. GRB 240606B: 7DT Optical upper limits
  55. GRB 241228B: Swift-XRT afterglow detection
  56. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  57. Fermi GRB 241228B: Global MASTER-Net observations report
  58. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  59. GRB 241228A: Swift-XRT refined Analysis
  60. GRB 241228A: Swift detection of a burst
  61. GRB 241217A/EP241217b: continued SOAR observations
  62. Fermi GRB 241226A: Global MASTER-Net observations report
  63. Fermi trigger No 756678579: Global MASTER-Net observations report
  64. IceCube Alert 241224.30: Global MASTER-Net observations report
  65. EP241223a: Global MASTER-Net observations report
  66. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  67. GRB241113A: 7DT Optical upper limits
  68. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  69. Fermi GRB 241223A: Global MASTER-Net observations report
  70. GRB 241223A: GOTO optical observations summary
  71. EP241217a: e-MERLIN radio observations
  72. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  73. Fermi trigger No 756447119: Global MASTER-Net observations report
  74. GRB 241217A/EP241217b: SOAR afterglow detection
  75. EP241217a: Liverpool Telescope optical upper limit
  76. GRB 241218A: Mondy AZT-33IK optical upper limit
  77. Konus-Wind detection of GRB 241204A (short/hard)
  78. EP 241217a: NIR detection with P200/WIRC
  79. GRB 241217A / EP241217b: NOT optical upper limits
  80. GRB 241218A: Swift-XRT refined Analysis
  81. EP241119a: 7DT Optical upper limits
  82. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  83. EP241217a: Global MASTER-Net observations report
  84. GRB 241218A: Swift detection of a burst
  85. EP241217a: Swift-XRT Detection
  86. EP241217a: EP detection of an X-ray transient
  87. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  88. Konus-Wind detection of GRB 241213A (EP 241213a)
  89. The EP-WXT trigger 01709128948 is likely a flaring star
  90. GRB 241215A: A long GRB detected by INTEGRAL
  91. GRB 241213A: Swift-XRT refined Analysis
  92. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  93. GRB 241213B: MAXI/GSC detection
  94. GRB 241213A: Swift detection of a burst
  95. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  96. Konus-Wind detection of GRB 241209B
  97. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  98. Konus-Wind detection of GRB 241209D
  99. GRB 241209C: Fermi GBM Observation
  100. GRB 241209A: Swift-XRT refined Analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov