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"

7445 results found.

  1. LIGO/Virgo/KAGRA S231008ap: Updated Sky localization
  2. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  3. LIGO/Virgo/KAGRA S231005ah: Updated Sky localization
  4. LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate
  5. LIGO/Virgo/KAGRA S231005j: Updated Sky localization
  6. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  7. IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
  8. transient AT2023sva: radio observations with AMI-LA
  9. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  12. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  13. LIGO/Virgo/KAGRA S230930al: Updated Sky localization
  14. LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
  15. LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  18. AT2023sva / GRB230916B: GIT observations of the afterglow
  19. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  20. LIGO/Virgo/KAGRA S230927be: Updated Sky localization
  21. LIGO/Virgo/KAGRA S230927l: Updated Sky localization
  22. LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  25. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  29. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  30. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  31. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  32. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  36. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  37. Fermi GBM Statement for Trigger 716527670/230916144
  38. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  39. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  40. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  41. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  42. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  43. AT 2023sva: NOT observations of the ZTF candidate afterglow
  44. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  45. LIGO/Virgo/KAGRA S230918aq: Retraction of GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  47. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  48. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  49. GRB 230911A: Swift-XRT afterglow detection
  50. LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
  51. IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
  52. LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
  53. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  54. GRB 230911A: Swift ToO observations
  55. GRB 230911A: GOTO optical counterpart candidate
  56. LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
  57. GRB 230906A: Chandra detection of the X-ray afterglow
  58. LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
  59. GRB 230911C: GOTO optical upper limits
  60. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
  61. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  62. GRB 230906A: Swift ToO observations
  63. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  64. LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
  65. LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
  66. LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
  67. GRB 230903A: Swift detection of a burst
  68. LIGO/Virgo/KAGRA S230831e: Updated Sky localization
  69. LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S230715bw: Reissue of Retraction of GW compact binary merger candidate
  71. LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
  73. GRB 230827B: Swift ToO observations
  74. LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
  75. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  76. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  77. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  78. GRB 230826A: Mondy optical observations
  79. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  80. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  81. LIGO/Virgo/KAGRA S230825k: Updated Sky localization
  82. LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
  83. GRB 230824A: AKO Optical Afterglow Candidate
  84. LIGO/Virgo/KAGRA S230824r: Updated Sky localization
  85. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  87. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  88. LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
  89. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  92. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  93. GRB 230818A: Swift detection of a burst
  94. GRB 230816A: Swift detection of a burst
  95. GRB 230815A: Swift detection of a burst
  96. GRB 230812B: AMI-LA radio detection of afterglow candidate
  97. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  98. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  99. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  100. GRB 230812B: GIT optical follow-up

Advanced

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