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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"
  1. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  2. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  3. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  4. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  5. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  6. GRB 230712B: Fermi GBM Final Localization
  7. LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
  8. GRB 230707A: Swift/BAT-GUANO position correction
  9. GRB 230712A: Fermi GBM Final Real-time Localization
  10. IceCube-230708A - Correction to GCN Circular 34170
  11. Fermi trigger No 710741042: Global MASTER-Net observations report
  12. GRB 230709C: GRBAlpha detection
  13. GRB 230709B: GRBAlpha detection
  14. GRB 230709C: Fermi GBM Detection
  15. GRB 230709C: Fermi GBM Final Localization
  16. GRB 230707B: Fermi GBM Observation
  17. GRB 230710A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  19. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
  20. IceCube-230707A: No candidates detected by Swift-XRT
  21. Swift Trigger 1178410 is not an astrophysical event
  22. GRB 230709C: AstroSat CZTI detection
  23. LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
  24. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  25. GRB 230703A detected with multiple GRID detectors
  26. GRB 230709C: BALROG localization (Fermi Trigger 710617111 / GRB 230709735)
  27. LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
  28. IceCube-230707A: No candidates from the Zwicky Transient Facility
  29. Fermi-LAT gamma-ray observations of IceCube-230708A
  30. Fermi-LAT gamma-ray observations of IceCube-230707B
  31. Fermi-LAT gamma-ray observations of IceCube-230707A
  32. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  34. GRB 230709B: BALROG localization (Fermi Trigger 710614579 / GRB 230709706)
  35. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  36. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
  38. LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
  39. Swift Trigger 1178410: possible GRB 230709A
  40. LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
  41. LIGO/Virgo/KAGRA S230708bi: Retraction of GW compact binary merger candidate
  42. GRB 230628C: GRID Detection
  43. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  44. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  45. GRB 230707A: Swift-XRT observations
  46. IceCube Alert 230708.35: Global MASTER-Net observations report
  47. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  48. GRB 230707B: Fermi GBM Final Real-time Localization
  49. IceCube Alert 230707.71: Global MASTER-Net observations report
  50. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 230707A: Fermi GBM Detection
  52. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  53. GRB 230707A: Swift ToO observations
  54. GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
  55. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  56. Fermi GRB 230707A: Global MASTER-Net observations report
  57. GRB 230707A: Fermi GBM Final Real-time Localization
  58. LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
  59. Integral GRB230706.70: Global MASTER-Net observations report
  60. LIGO/Virgo/KAGRA S230704f: Updated Sky localization
  61. LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
  62. IBAS trigger number 10311: not a real GRB
  63. LIGO/Virgo/KAGRA S230702an: Updated Sky localization
  64. GRB 230625A: Detection by GRID
  65. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  66. LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  68. ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
  69. Fermi trigger No 710117592: Global MASTER-Net observations report
  70. GRB 230626A: VZLUSAT-2 detection
  71. LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
  72. GRB 230328B: LBT detection of the likely host galaxy
  73. LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
  74. Konus-Wind detection of GRB 220623A
  75. GRB 230701B: AstroSat CZTI detection
  76. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  77. LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate
  78. GRB 230628E: Swift/UVOT Detection
  79. GRB 230628E: Swift-BAT refined analysis
  80. GRB 230702A: Fermi GBM Final Real-time Localization
  81. GRB 230628E: ATCA rapid radio follow-up
  82. GRB 230701A: Fermi GBM Final Real-time Localization
  83. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  84. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
  85. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  86. LIGO/Virgo/KAGRA S230630bq: Identification of a GW compact binary merger candidate
  87. IPN triangulation of GRB 230625B (ultra-long)
  88. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  89. LIGO/Virgo/KAGRA S230630am: Identification of a GW compact binary merger candidate
  90. GRB 230625B: CALET Gamma-Ray Burst Monitor detection
  91. GRB 230628E - VLT spectroscopic observations
  92. ZTF23aaoohpy/AT2023lcr: LBT observations
  93. Fermi GRB 230628C: Global MASTER-Net observations report
  94. GRB 230625B: AstroSat CZTI detection
  95. GRB230628E: VLT optical identification of afterglow candidate
  96. GRB 230628E: Swift-XRT refined Analysis
  97. GRB 230628E: Enhanced Swift-XRT position (Correction to name in GCN 34115)
  98. GRB 230628A: Enhanced Swift-XRT position
  99. Fermi GRB 230628D: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate

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