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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"

36155 results found.

  1. GRB 230814A: Fermi GBM Final Real-time Localization
  2. GRB 230812B: Koshka Zeiss-1000 optical observations
  3. GRB 230812B: GIT optical follow-up
  4. GRB 230812B: Leavitt Observatory optical observations
  5. GRB 230812B : optical observations from Observatoire de Haute-Provence
  6. GRB 230812B: Bassano Bresciano Observatory optical observations
  7. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  8. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  9. GRB 230812B: rest-frame energetics from Konus-Wind observation
  10. GRB 230812B: OASDG optical observations
  11. GRB 230812B: AbAO optical observations
  12. GRB 230812B: Spectroscopy from NOT
  13. GRB 230812B: Redshift from OSIRIS+/GTC
  14. GRB 230812B: Montarrenti Observatory optical observations
  15. GRB 230812B: SAO RAS optical observations
  16. GRB 230812B: Detected Optical Afterglow Candidate
  17. GRB 230812B: GMG - GRANDMA observations
  18. Konus-Wind detection of GRB 230812B
  19. GRB230812B: AGILE/MCAL detection
  20. GRB 230812B: GECAM-C observation of a very bright burst
  21. GRB 230812B: Swift-XRT afterglow detection
  22. GRB 230812: Swift/UVOT Detection
  23. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  24. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  25. Fermi GRB 230812B: MASTER optical counterpart
  26. GRB 230812B: KAIT Optical Afterglow Candidate
  27. GRB 230812B: Improved Swift/XRT localization
  28. GRB 230812B: Preliminary Swift/XRT localization
  29. GRB 230812B: Fermi-LAT detection
  30. GRB 230812B: Fermi GBM Observation of a very bright burst
  31. Fermi GRB 230812B: Global MASTER-Net observations report
  32. GRB 230812B: Tiled Swift observations
  33. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  34. GRB 230812B: Fermi GBM Final Real-time Localization
  35. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  36. GRB 230812A: Fermi GBM Final Real-time Localization
  37. GRB 230808A: Fermi GBM Detection
  38. GRB 230805B: Swift-BAT refined analysis
  39. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  40. GRB 230805B: AstroSat CZTI detection
  41. GRB 230808A: Swift/BAT-GUANO detection of a burst
  42. GRB 230808B: Fermi GBM Final Real-time Localization
  43. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  44. GRB 230808A: Fermi GBM Final Real-time Localization
  45. GRB 230805B : MITSuME Akeno optical upper limits
  46. Fermi GRB 230807A: Global MASTER-Net observations report
  47. GRB 230807A: Fermi GBM Final Real-time Localization
  48. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  49. Konus-Wind detection of GRB 230803A
  50. GRB 230805B: Fermi GBM observation
  51. GRB 230805B : OHP/T193 optical upper limit
  52. GRB 230806A: Fermi GBM Final Localization
  53. GRB 230805B: Enhanced Swift-XRT position
  54. GRB 230805B: Swift/UVOT Upper Limits
  55. GRB 230805B: Bassano Bresciano observatory upper limit
  56. GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
  57. GRB 230805B: NOT optical afterglow confirmation
  58. GRB 230805B: Swift-XRT refined Analysis
  59. Fermi GRB 230805A: Global MASTER-Net observations report
  60. GRB 230805B: SAO RAS optical observations
  61. Swift GRB 230805B: Global MASTER-Net observations report
  62. GRB 230805B: Swift detection of a burst
  63. GRB 230805A: Fermi GBM Final Real-time Localization
  64. GRB 230802B: AstroSat CZTI detection
  65. GRB 230802A: Fermi GBM observation
  66. GRB 230802A: Swift-BAT refined analysis
  67. GRB 230804A: Fermi GBM Final Real-time Localization
  68. IPN triangulation of GRB 230803A
  69. GRB 230802A: Swift/UVOT Upper Limits
  70. GRB 230803A: AstroSat CZTI detection
  71. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  72. GRB 230803A: Fermi GBM Final Real-time Localization
  73. GRB 230802B: Fermi GBM Final Localization
  74. Swift GRB 230802A: Global MASTER-Net observations report
  75. GRB 230802A: BOOTES-5/JGT optical upper limit
  76. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  77. GRB 230802A: Swift-XRT refined Analysis
  78. GRB 230802A: Enhanced Swift-XRT position
  79. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  80. GRB 230802A: Swift detection of a burst
  81. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  82. GRB 230723A: SPT-3G millimeter-band transient event inconsistent with IPN position
  83. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  84. GRB 230731A: Fermi GBM Final Real-time Localization
  85. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  86. GRB 230728A: Swift-BAT refined analysis
  87. GRB 230723B: Swift-BAT refined analysis
  88. GRB 230723B: MITSuME Ishigaki optical observation
  89. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 230728A: BOOTES-1 optical upper limit
  91. GRB 230728A: Fermi GBM Observation
  92. GRB 230728A: LCOGT Optical Upper Limit
  93. GRB 230728A: Swift/UVOT Upper Limits
  94. GRB 230728A: Swift-XRT refined Analysis
  95. GRB 230728A: Enhanced Swift-XRT position
  96. GRB 230728A: NOT optical observations and possible host galaxy
  97. GRB 230727A: AstroSat CZTI detection
  98. GRB 230728A: Swift detection of a burst
  99. GRB 230727A: Swift/BAT-GUANO detection of a burst
  100. GRB 230727A: Fermi GBM Final Real-time Localization

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