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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"

27289 results found.

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

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