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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"

36143 results found.

  1. GRB 231118A: Swift detection of a burst
  2. GRB 231118A: Fermi GBM Final Real-time Localization
  3. GRB 231117A: Lowell Discovery Telescope Observations
  4. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  5. GRB 231117A: ATCA detection of a radio counterpart
  6. GRB 231117A: GRBAlpha detection
  7. GRB 231117A: Keck spectroscopy of afterglow candidate
  8. GRB 231115A: Wendelstein Optical/Infrared Observations
  9. GRB 231115A: JinShan optical upper limits
  10. GRB 231117A: GIT optical follow-up
  11. GRB 231117A: LT observations consistent with fading
  12. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  13. GRB 231117A: REM optical and NIR early-time observations
  14. GRB231117A: AGILE/MCAL analysis
  15. GRB 231117A: AKO Optical Upper Limit
  16. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  17. Swift GRB 231117A: Global MASTER-Net observations report
  18. GRB 231117A (short): Glowbug gamma-ray detection
  19. GRB 231117A: ATLAS non-detection of an optical counterpart
  20. Konus-Wind detection of GRB 231117A (short/hard)
  21. GRB 231115A : OHP/T120 optical upper limit
  22. GRB 231115A: optical observations from INAF observatories
  23. GRB 231117A : MITSuME Akeno optical upper limits
  24. GRB 231117A: AGILE detection of a bright short burst
  25. GRB 231117A: Enhanced Swift-XRT position
  26. GRB 231117A: GOTO optical upper limits
  27. GRB 231117A: AstroSat CZTI detection of a bright short burst
  28. GRB 231117A: Swift detection of a bright short burst
  29. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  30. GRB 231111A: Swift/UVOT Detection
  31. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  32. GRB231115A: Liverpool Telescope imaging
  33. GRB 231115A: NuSTAR Follow-Up Observations
  34. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  35. GRB 231115A: Swift-XRT and Swift-UVOT observations
  36. Fermi GRB 231116A: Global MASTER-Net observations report
  37. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  38. GRB 231115A: AGILE/MCAL upper limits
  39. GRB 231115A: Insight-HXMT/HE detection
  40. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  41. GRB 231116A: Fermi GBM Final Real-time Localization
  42. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  43. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  44. GRB 231115A / AT2023xvj: Updated GIT analysis
  45. GRB 231115A: archival Chandra X-ray observations
  46. GRB 231115A: Upper limits from a neutrino search with IceCube
  47. GRB 231115A: Kinder observations with Lulin observatory
  48. GRB231115A: GRANDMA Observations
  49. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  50. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  51. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  52. GRB 231106A: TESS identification of candidate optical counterpart
  53. GRB 231115A: MASTER optical observations
  54. GRB 231115A (short): Glowbug gamma-ray detection
  55. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  56. GRB 231115A: archival HST observations
  57. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  58. GRB 231115A: Swift ToO observations
  59. Fermi GRB 231115A: Global MASTER-Net observations report
  60. GRB 231115A: significance of INTEGRAL localization alignment with M82
  61. GRB 231115A: a short hard GRB detected by IBAS, poistionally coincident with M82
  62. GRB 231115A position consistent with M 82 galaxy
  63. GRB 231115A: Fermi GBM Final Real-time Localization
  64. GRB 231111A: Swift-BAT refined analysis
  65. Fermi GRB 231114A: Global MASTER-Net observations report
  66. GRB 231113A (short): Glowbug gamma-ray detection
  67. GRB 231114A (short): Glowbug gamma-ray detection
  68. GRB 231114A: Fermi GBM Final Localization
  69. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  70. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  71. GRB 231110A: CALET Gamma-Ray Burst Monitor detection
  72. GRB 231110A: Swift-BAT refined analysis
  73. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  74. GRB 231106A: Glowbug gamma-ray detection
  75. GRB 231111A: Xinglong-2.16m optical observations
  76. GRB 231110A: Swift-UVOT Upper Limits
  77. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  78. GRB 231104A: VZLUSAT-2 detection
  79. GRB 231111A: TNG tentative redshift
  80. GRB 231110A: Glowbug gamma-ray detection
  81. GRB 231110A: AstroSat CZTI detection
  82. GRB 231111A NUTTelA-TAO / BSTI Early Measurements
  83. GRB 231111A: Leavitt Observatory optical observations
  84. GRB231111A: Optical follow-up observations with Mephisto
  85. GRB 231111A: GMG observation (correction)
  86. GRB 231111A: GMG observation upper limit
  87. GRB 231106B: GRBAlpha detection
  88. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  89. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  90. GRB 231111A: Swift-XRT refined Analysis
  91. GRB 231111A: Mondy optical observations
  92. GRB 231111A: GECAM-C detection of a long burst (correction)
  93. GRB 231110A: GECAM-B detection (correction)
  94. GRB 231111A: Enhanced Swift-XRT position
  95. GRB 231111A: GECAM-C detection of a long burst
  96. GRB 231110A: GECAM detection
  97. GRB 231110A: GOTO optical upper limits
  98. GRB 231110A: SAO RAS optical observations
  99. GRB 231110A: Swift-XRT afterglow detection
  100. GRB231111A: YAHPT Observations

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