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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').
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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"

27784 results found.

  1. GRB 231122B: CALET Gamma-Ray Burst Monitor detection
  2. GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  3. GRB 231117A: Chandra afterglow detection
  4. GRB 231123A: Fermi GBM Final Real-time Localization
  5. GRB 231122B: Glowbug gamma-ray detection
  6. GRB 231122A: GECAM detection
  7. GRB 231122B: GECAM detection
  8. GRB 231122A: Fermi GBM Final Real-time Localization
  9. GRB 231118A: ATCA detection of radio counterpart
  10. GRB 231117A: Swift/UVOT late time observations
  11. GRB 231117A: Swift-BAT refined analysis
  12. GRB 231118A: GRBAlpha detection
  13. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  14. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  15. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  17. GRB 231118A: VZLUSAT-2 detection
  18. GRB 231118A: Swift-BAT refined analysis
  19. Konus-Wind detection of GRB 231020A
  20. GRB 231118B: CALET Gamma-Ray Burst Monitor detection
  21. GRB 231117A: CALET Gamma-Ray Burst Monitor detection
  22. 231118A: Swift-UVOT Detection
  23. GRB231117A: Swift-UVOT detection
  24. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  25. GRB 231118A: Fermi GBM observation
  26. GRB 231120A: Fermi GBM Final Real-time Localization
  27. GRB 231117A: Swift-XRT refined Analysis
  28. GRB 231118A: Swift-XRT refined Analysis
  29. GRB 231118A: MeerLICHT afterglow detection
  30. GRB 231118A: VLT/X-shooter redshift
  31. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  32. GRB 231117A: GECAM-C detection
  33. GRB 231118A: AstroSat CZTI detection
  34. GRB 231115A: Upper limit from CALET Gamma-Ray Burst Monitor
  35. GRB 231117A: 10 GHz VLA detection
  36. GRB 231118A: Las Cumbres optical detection
  37. GRB 231118B: Fermi GBM Final Real-time Localization
  38. GRB 231118A: LCOGT Optical Observations
  39. GRB 231118A: MASTER OT observation
  40. GRB 231118A: Continued Skynet Observations
  41. Swift GRB231118.72: Global MASTER-Net observations report
  42. GRB 231118A: Enhanced Swift-XRT position
  43. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  44. GRB 231118A: Swift-XRT position
  45. GRB 231118A: Skynet Optical Afterglow Discovery
  46. GRB 231118A: Swift detection of a burst
  47. GRB 231118A: Fermi GBM Final Real-time Localization
  48. GRB 231117A: ATCA detection of a radio counterpart
  49. GRB 231117A: GRBAlpha detection
  50. GRB 231117A: GIT optical follow-up
  51. GRB 231117A: AKO Optical Upper Limit
  52. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  53. Swift GRB 231117A: Global MASTER-Net observations report
  54. GRB 231117A (short): Glowbug gamma-ray detection
  55. GRB 231117A: ATLAS non-detection of an optical counterpart
  56. Konus-Wind detection of GRB 231117A (short/hard)
  57. GRB 231115A: optical observations from INAF observatories
  58. GRB 231117A : MITSuME Akeno optical upper limits
  59. GRB 231117A: AGILE detection of a bright short burst
  60. GRB 231117A: Enhanced Swift-XRT position
  61. GRB 231117A: GOTO optical upper limits
  62. GRB 231117A: AstroSat CZTI detection of a bright short burst
  63. GRB 231117A: Swift detection of a bright short burst
  64. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  65. GRB 231111A: Swift/UVOT Detection
  66. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  67. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  68. GRB 231115A: Swift-XRT and Swift-UVOT observations
  69. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  70. GRB 231115A: Insight-HXMT/HE detection
  71. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  72. GRB 231116A: Fermi GBM Final Real-time Localization
  73. GRB 231115A / AT2023xvj: Updated GIT analysis
  74. GRB231115A: GRANDMA Observations
  75. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  76. GRB 231106A: TESS identification of candidate optical counterpart
  77. GRB 231115A (short): Glowbug gamma-ray detection
  78. GRB 231115A: Swift ToO observations
  79. GRB 231115A: Fermi GBM Final Real-time Localization
  80. GRB 231111A: Swift-BAT refined analysis
  81. LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
  82. GRB 231113A (short): Glowbug gamma-ray detection
  83. GRB 231114A (short): Glowbug gamma-ray detection
  84. GECAM-B observation of a short burst from SGR J1555-5402
  85. GRB 231114A: Fermi GBM Final Localization
  86. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  87. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  88. GRB 231110A: CALET Gamma-Ray Burst Monitor detection
  89. GRB 231110A: Swift-BAT refined analysis
  90. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  91. GRB 231106A: Glowbug gamma-ray detection
  92. GRB 231111A: Xinglong-2.16m optical observations
  93. GRB 231110A: Swift-UVOT Upper Limits
  94. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  95. GRB 231104A: VZLUSAT-2 detection
  96. GRB 231111A: TNG tentative redshift
  97. GRB 231110A: Glowbug gamma-ray detection
  98. GRB 231110A: AstroSat CZTI detection
  99. GRB 231111A: Leavitt Observatory optical observations
  100. GRB231111A: Optical follow-up observations with Mephisto

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