Skip to main content
Circulars over Kafka event name backfill. 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"

24598 results found.

  1. GRB 231117A: ATLAS non-detection of an optical counterpart
  2. GRB 231115A : OHP/T120 optical upper limit
  3. GRB 231117A : MITSuME Akeno optical upper limits
  4. GRB 231117A: Enhanced Swift-XRT position
  5. GRB 231117A: AstroSat CZTI detection of a bright short burst
  6. GRB 231117A: Swift detection of a bright short burst
  7. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  8. GRB 231111A: Swift/UVOT Detection
  9. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  10. GRB231115A: Liverpool Telescope imaging
  11. GRB 231115A: NuSTAR Follow-Up Observations
  12. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  13. GRB 231115A: Swift-XRT and Swift-UVOT observations
  14. GRB 231115A: AGILE/MCAL upper limits
  15. GRB 231115A: Insight-HXMT/HE detection
  16. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  17. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  18. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  19. GRB 231115A / AT2023xvj: Updated GIT analysis
  20. GRB 231115A: Upper limits from a neutrino search with IceCube
  21. GRB 231115A: Kinder observations with Lulin observatory
  22. GRB231115A: GRANDMA Observations
  23. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  24. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  25. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  26. GRB 231106A: TESS identification of candidate optical counterpart
  27. GRB 231115A (short): Glowbug gamma-ray detection
  28. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  29. GRB 231115A: archival HST observations
  30. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  31. GRB 231115A: significance of INTEGRAL localization alignment with M82
  32. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  33. GRB 231111A: Swift-BAT refined analysis
  34. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  35. GRB 231113A (short): Glowbug gamma-ray detection
  36. GRB 231114A (short): Glowbug gamma-ray detection
  37. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  38. GECAM-B observation of a short burst from SGR J1555-5402
  39. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  40. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  41. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  42. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  43. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  44. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  45. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  47. GRB 231110A: Swift-BAT refined analysis
  48. GRB 231106A: Glowbug gamma-ray detection
  49. GRB 231111A: Xinglong-2.16m optical observations
  50. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  51. GRB 231104A: VZLUSAT-2 detection
  52. GRB 231110A: Glowbug gamma-ray detection
  53. GRB 231111A: Leavitt Observatory optical observations
  54. GRB231111A: Optical follow-up observations with Mephisto
  55. GRB 231111A: GMG observation (correction)
  56. GRB 231111A: GMG observation upper limit
  57. GRB 231106B: GRBAlpha detection
  58. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  59. GRB 231111A: Swift-XRT refined Analysis
  60. GRB 231111A: Mondy optical observations
  61. GRB 231111A: Enhanced Swift-XRT position
  62. GRB 231110A: SAO RAS optical observations
  63. GRB231111A: GIT confirmation of the optical afterglow
  64. GRB 231111A: Nanshan/HMT optical observations
  65. GRB 231111A: Swift detection of a burst with an optical counterpart
  66. Swift GRB231111.60: Global MASTER-Net observations report
  67. GRB231110A: WFST Observation and upper limits
  68. GRB 231110A: Swift detection of a burst
  69. LIGO/Virgo/KAGRA S231110g: Updated Sky localization
  70. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  71. LIGO/Virgo/KAGRA S231108u: Updated Sky localization
  72. LIGO/Virgo/KAGRA O4 Landscape
  73. LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
  74. GRB 231104A: Swift-BAT refined analysis
  75. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  76. GRB 231104A: NuSTAR Observation of the prompt emission
  77. GRB 231104A: 3.6m DOT optical upper limit
  78. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  79. LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
  80. Fermi-LAT gamma-ray observations of IceCube-231103A
  81. GRB 231104A: NOT upper limit
  82. GRB 231104A: Fermi GBM Observation
  83. Fermi GRB 231103A: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
  85. GRB 231104A: AKO Upper Limit
  86. GRB 231104A: AstroSat CZTI detection
  87. GRB 231104A: Swift-XRT refined Analysis
  88. GRB 231104A: Fermi-LAT detection
  89. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  90. GRB 231104A: Swift/UVOT Upper Limits
  91. GRB 231104A: Enhanced Swift-XRT position
  92. GRB231104A: LCOGT Optical Upper Limits
  93. GRB 231104A: Swift detection of a bright burst
  94. Fermi-LAT gamma-ray observations of IceCube-231027A
  95. LIGO/Virgo/KAGRA S231102w: Updated Sky localization
  96. GRB 231101A: Glowbug gamma-ray detection
  97. LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
  98. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  99. GRB 231101A: Fermi GBM Final Real-time Localization
  100. GRB 231028B: VZLUSAT-2 detection

Advanced

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