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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. GRB 231118B: BALROG localization (Fermi Trigger 722039659 / GRB 231118940)
  2. GRB 231118B: Fermi GBM Final Real-time Localization
  3. GRB 231118A: LCOGT Optical Observations
  4. GRB 231118A: MASTER OT observation
  5. GRB 231118A: Continued Skynet Observations
  6. Swift GRB231118.72: Global MASTER-Net observations report
  7. GRB 231118A: Enhanced Swift-XRT position
  8. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  9. GRB 231118A: Swift-XRT position
  10. GRB 231118A: Skynet Optical Afterglow Discovery
  11. GRB 231117A: SOAR/Goodman imaging of the afterglow
  12. GRB 231118A: Swift detection of a burst
  13. GRB 231118A: Fermi GBM Final Real-time Localization
  14. GRB 231117A: Lowell Discovery Telescope Observations
  15. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  16. GRB 231117A: ATCA detection of a radio counterpart
  17. LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
  18. GRB 231117A: GRBAlpha detection
  19. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  20. GRB 231117A: Keck spectroscopy of afterglow candidate
  21. GRB 231115A: Wendelstein Optical/Infrared Observations
  22. GRB 231115A: JinShan optical upper limits
  23. LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
  24. GRB 231117A: GIT optical follow-up
  25. GRB 231117A: LT observations consistent with fading
  26. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  27. GRB 231117A: REM optical and NIR early-time observations
  28. GRB231117A: AGILE/MCAL analysis
  29. GRB 231117A: AKO Optical Upper Limit
  30. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  31. Swift GRB 231117A: Global MASTER-Net observations report
  32. GRB 231117A (short): Glowbug gamma-ray detection
  33. GRB 231117A: ATLAS non-detection of an optical counterpart
  34. Konus-Wind detection of GRB 231117A (short/hard)
  35. GRB 231115A : OHP/T120 optical upper limit
  36. GRB 231115A: optical observations from INAF observatories
  37. GRB 231117A : MITSuME Akeno optical upper limits
  38. GRB 231117A: AGILE detection of a bright short burst
  39. GRB 231117A: Enhanced Swift-XRT position
  40. GRB 231117A: GOTO optical upper limits
  41. GRB 231117A: AstroSat CZTI detection of a bright short burst
  42. GRB 231117A: Swift detection of a bright short burst
  43. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  44. GRB 231111A: Swift/UVOT Detection
  45. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  46. GRB231115A: Liverpool Telescope imaging
  47. GRB 231115A: NuSTAR Follow-Up Observations
  48. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  49. GRB 231115A: Swift-XRT and Swift-UVOT observations
  50. Fermi GRB 231116A: Global MASTER-Net observations report
  51. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  52. GRB 231115A: AGILE/MCAL upper limits
  53. GRB 231115A: Insight-HXMT/HE detection
  54. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  55. GRB 231116A: Fermi GBM Final Real-time Localization
  56. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  57. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  58. GRB 231115A / AT2023xvj: Updated GIT analysis
  59. GRB 231115A: archival Chandra X-ray observations
  60. GRB 231115A: Upper limits from a neutrino search with IceCube
  61. GRB 231115A: Kinder observations with Lulin observatory
  62. GRB231115A: GRANDMA Observations
  63. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  64. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  65. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  66. GRB 231106A: TESS identification of candidate optical counterpart
  67. GRB 231115A: MASTER optical observations
  68. GRB 231115A (short): Glowbug gamma-ray detection
  69. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  70. GRB 231115A: archival HST observations
  71. Integral GRB231115.65: Global MASTER-Net observations report
  72. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  73. GRB 231115A: Swift ToO observations
  74. Fermi GRB 231115A: Global MASTER-Net observations report
  75. GRB 231115A: significance of INTEGRAL localization alignment with M82
  76. GRB 231115A: a short hard GRB detected by IBAS, poistionally coincident with M82
  77. GRB 231115A position consistent with M 82 galaxy
  78. GRB 231115A: Fermi GBM Final Real-time Localization
  79. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  80. GRB 231111A: Swift-BAT refined analysis
  81. LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
  82. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  83. Fermi GRB 231114A: Global MASTER-Net observations report
  84. GRB 231113A (short): Glowbug gamma-ray detection
  85. GRB 231114A (short): Glowbug gamma-ray detection
  86. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  87. GECAM-B observation of a short burst from SGR J1555-5402
  88. GRB 231114A: Fermi GBM Final Localization
  89. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  90. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  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. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  95. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  96. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  97. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  98. GRB 231110A: Swift-BAT refined analysis
  99. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  100. GRB 231106A: Glowbug gamma-ray detection

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