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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"

28050 results found.

  1. GRB 230911D: Fermi GBM observation
  2. IPN triangulation of GRB 230911D (long)
  3. GRB230911C: LCOGT Optical Upper Limits
  4. LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
  5. GRB 230911C: Swift/UVOT Upper Limits
  6. GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
  7. Fermi trigger No 716145795: Global MASTER-Net observations report
  8. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  9. GRB 230911C: Enhanced Swift-XRT position
  10. GRB 230911D: BALROG localization (Fermi Trigger 716111594/ GRB 230911329)
  11. GRB 230911C: Swift detection of a burst
  12. GRB 230906A: BlackGEM upper limits
  13. GRB 230903A: TESS observations of optical emission
  14. GRB 230906A: AstroSat CZTI detection
  15. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
  16. Glowbug gamma-ray detection GRB 230905B
  17. GRB 230906A: Swift/UVOT Upper Limits
  18. GRB 230818A: radio observation with the VLA
  19. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  20. GRB 230906A: Swift-XRT observations
  21. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  22. GRB 230905B: GECAM-C detection of a long burst
  23. LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
  24. LIGO/Virgo/KAGRA S230819ax: Correction to PROB_BBH and PROB_TERRES probabilities
  25. GRB 230903A: Swift-XRT refined Analysis
  26. GRB 230903A: Enhanced Swift-XRT position
  27. GRB 230903A: VLT/X-shooter optical observations
  28. GRB 230903A: Swift-BAT refined analysis
  29. Fermi trigger No 715429986: Global MASTER-Net observations report
  30. GRB 230903A: Fermi GBM detection
  31. LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
  32. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  33. LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
  34. GRB 230903A: LCOGT Optical Upper Limits
  35. GRB 230903A: Swift detection of a burst
  36. LIGO/Virgo/KAGRA S230831e: Updated Sky localization
  37. LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
  38. GRB 230827B: Glowbug gamma-ray detection
  39. GRB 230827A: Glowbug gamma-ray detection
  40. GRB 230826A: Glowbug gamma-ray detection
  41. GRB 230827B: Swift-XRT afterglow detection
  42. LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
  43. LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
  44. GRB 230827A: Fermi GBM Observation
  45. GRB 230826A: Swift-BAT refined analysis
  46. GRB 230827A: VZLUSAT-2 detection
  47. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  48. GRB 230826A: VZLUSAT-2 detection
  49. GRB 230827B: VZLUSAT-2 detection
  50. GRB 230827B / GRB 230827256: Fermi GBM Observation
  51. Subject: GRB230826A: Swift/UVOT upper limits
  52. GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
  53. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  54. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  55. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  56. GRB 230826A: Fermi GBM Observation
  57. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  58. GRB 230826A: Enhanced Swift-XRT position
  59. GRB 230826A: Swift-XRT refined Analysis
  60. GRB 230826A: Mondy optical observations
  61. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  62. GRB 230826A: Swift detection of a burst
  63. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  64. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  65. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  66. GRB 230812B: radio detection with the VLA
  67. LIGO/Virgo/KAGRA S230825k: Updated Sky localization
  68. LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
  69. GRB 230824A: AKO Optical Afterglow Candidate
  70. LIGO/Virgo/KAGRA S230824r: Updated Sky localization
  71. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  73. GRB 230822A: Swift/BAT-GUANO detection of a burst
  74. GRB 230818B: VZLUSAT-2 detection
  75. LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
  76. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  77. GRB 230812B: Assy optical observations, possible SN rise
  78. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  79. GRB 230818A: Swift-BAT refined analysis
  80. GRB 20230818A: GIT optical upper limit
  81. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  82. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  83. Swift Triggers 1186280 and 1186291 are not GRBs
  84. GRB 230818A: Fermi GBM Observation
  85. GRB 230812B: GIT Confirmation of SN rise
  86. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  87. GRB 230818A: Nickel and KAIT telescope optical observations
  88. GRB 230812B: SAO RAS Zeiss-1000 observations
  89. GRB 230818A: further SAO RAS Zeiss-1000 observations
  90. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  91. GRB 230818A: AKO Upper Limit
  92. GRB 230818A: Tautenburg observations
  93. GRB 230818A: Leavitt Observatory upper limit
  94. GRB 230818A: Swift-XRT refined Analysis
  95. GRB 230818A: Bassano Bresciano Observatory optical observations
  96. GRB 230818A: KGO RC-25 optical observations
  97. GRB 230818A: Swift/UVOT Detection
  98. GRB 230818A: Enhanced Swift-XRT position
  99. GRB 230818A: SAO RAS Zeiss-1000 observations
  100. Fermi trigger No 713974668: Global MASTER-Net observations report

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