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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"

30501 results found.

  1. LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
  2. GRB 230827B: Glowbug gamma-ray detection
  3. GRB 230827A: Glowbug gamma-ray detection
  4. GRB 230826A: Glowbug gamma-ray detection
  5. GRB 230827B: Swift-XRT afterglow detection
  6. LIGO/Virgo/KAGRA S230715bw: Reissue of Retraction of GW compact binary merger candidate
  7. LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
  8. GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
  9. GRB 230827B: Swift ToO observations
  10. LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
  11. GRB 230827A: Fermi GBM Observation
  12. GRB 230827B: CALET Gamma-Ray Burst Monitor detection
  13. GRB 230826A: Swift-BAT refined analysis
  14. GRB 230828A: AstroSat CZTI detection
  15. GRB 230827A: VZLUSAT-2 detection
  16. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  17. GRB 230826A: VZLUSAT-2 detection
  18. GRB 230827B: VZLUSAT-2 detection
  19. GRB 230827B / GRB 230827256: Fermi GBM Observation
  20. GRB 230827A: GRBAlpha detection
  21. Subject: GRB230826A: Swift/UVOT upper limits
  22. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  23. Fermi GRB 230827A: Global MASTER-Net observations report
  24. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  25. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  26. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  27. GRB 230826A: GRBAlpha detection
  28. GRB 230826A: Fermi GBM Observation
  29. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  30. GRB 230826A: Mondy optical observations
  31. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  32. GRB 230826A: Swift detection of a burst
  33. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  34. GRB 230824A: AKO Photometric Follow-up Observations
  35. GRB 230818B: CALET Gamma-Ray Burst Monitor detection
  36. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  37. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  38. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  39. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  40. GRB 230812B: radio detection with the VLA
  41. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  42. LIGO/Virgo/KAGRA S230825k: Updated Sky localization
  43. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  44. LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
  45. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  46. GRB 230824A: AKO Optical Afterglow Candidate
  47. Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  48. IBAS trigger 10375 is not a GRB
  49. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  50. LIGO/Virgo/KAGRA S230824r: Updated Sky localization
  51. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  52. GRB 230822A: Fermi GBM Observation
  53. GRB 230822A: Swift/BAT-GUANO detection of a burst
  54. IceCube-230823A: Event likely due to background
  55. GRB 230818B: VZLUSAT-2 detection
  56. GRB 230818B: AstroSat CZTI detection
  57. GRID detection of GRB 230818A
  58. LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
  59. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  60. GRB 230812B: Assy optical observations, possible SN rise
  61. GRB 230815A: ATCA detection of radio counterpart
  62. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  63. GRB 230818A: Swift-BAT refined analysis
  64. GRB 20230818A: GIT optical upper limit
  65. Konus-Wind detection of GRB 230818A
  66. Swift triggers 1186294-1186304 are not astrophysical transients
  67. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  68. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  69. GRB 230818A: Fermi GBM Observation
  70. GRB 230812B: GIT Confirmation of SN rise
  71. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  72. GRB 230818A: Nickel and KAIT telescope optical observations
  73. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  74. GRB 230812B: SAO RAS Zeiss-1000 observations
  75. GRB 230818A: further SAO RAS Zeiss-1000 observations
  76. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  77. GRB 230818A: AKO Upper Limit
  78. GRB 230818A: AstroSat CZTI detection
  79. GRB 230818A: Tautenburg observations
  80. GRB 230818A: Leavitt Observatory upper limit
  81. GRB 230818A: Bassano Bresciano Observatory optical observations
  82. GRB 230818A: KGO RC-25 optical observations
  83. GRB 230818A: Swift/UVOT Detection
  84. GRB 230818A: NOT photometry and spectroscopy
  85. GRB 230818A: SAO RAS Zeiss-1000 observations
  86. Fermi GRB 230818A: Global MASTER-Net observations report
  87. GRB 230818A: GOTO optical afterglow detection
  88. GRB 230812B: SAO RAS observations, possible re-brightening
  89. GRB 230816A: Swift-BAT refined analysis
  90. GRB 230816A: SVOM/C-GFT optical detection
  91. GRB 230817A: AstroSat CZTI detection
  92. GRB 230812B: SAO RAS optical observations
  93. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  94. GRB 230812B: NOEMA detection
  95. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  96. Fermi GRB 230817A: Global MASTER-Net observations report
  97. GRB 230812B: optical photometry from Konkoly
  98. GRB 230812B: SAO RAS optical observations
  99. GRB230816A: Possible host and GIT detection of optical counterpart
  100. GRB 230816A: Tautenburg observations

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