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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"

35433 results found.

  1. GRB 231018A: Fermi GBM Final Real-time Localization
  2. GRB 231017A: Swift ToO observations
  3. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  4. GRB231017A: Fermi GBM Final Localization
  5. IceCube-231014A: Upper limits from a search for additional neutrino events in IceCube
  6. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  7. Correction in GCN 34814: GRB 231012B (not GRB 231012A)
  8. GRB 231012A: Fermi GBM Final Real-time Localization
  9. GRB 231012A: Fermi GBM Final Real-time Localization
  10. GRB 231004A: Glowbug gamma-ray detection
  11. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  12. IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 231004A: CALET Gamma-Ray Burst Monitor detection
  14. Update of IceCube-231004A - Corrected direciton
  15. GRB 231004A: Fermi GBM Final Real-time Localization
  16. GRB 231003A is not a GRB
  17. GRB 231003A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  20. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  21. GRB 230827B: 10.4m GTC spectroscopic redshift
  22. GRB 230930A: Fermi GBM Final Real-time Localization
  23. AT2023sva / GRB230916B: GIT observations of the afterglow
  24. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  25. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  26. Konus-Wind detection of GRB 230919A
  27. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  30. Fermi Gamma-ray Burst Monitor trigger 717299390/230925076 is not a GRB
  31. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  32. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  33. GRB 230921A: Fermi GBM Final Real-time Localization
  34. GRB 230918B: VLT/X-shooter classification of AT 2023tbf (GOTO23aky) as a dwarf nova
  35. IPN triangulation of GRB 230919A (short)
  36. GRB 230919A: Fermi GBM Observation
  37. Fermi GBM Statement for Trigger 716527670/230916144
  38. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  39. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  40. GRB 230919A: AstroSat CZTI detection
  41. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  42. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  43. GRB 230919A: Fermi GBM Final Real-time Localization
  44. Detection of self-absorbed radio emission from GRB 230812B with the JVLA + uGMRT
  45. GRB 230918B: Fermi GBM Final Real-time Localization
  46. GRB 230918A (short): Glowbug gamma-ray detection
  47. GRB 230916B: Glowbug gamma-ray detection
  48. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  49. GRB 230915A: Fermi GBM observation
  50. GRB 230812B: Radio observations with the uGMRT
  51. GRB 230918A: Fermi GBM Final Real-time Localization
  52. GRB 230917A: AstroSat CZTI detection
  53. GRB 230915B: Glowbug gamma-ray detection
  54. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  55. GRB 230911A: Fermi GBM Observation
  56. GRB 230915A: Swift/BAT-GUANO detection of a burst
  57. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  58. GRB 230911D: GRBAlpha detection
  59. Swift Trigger 1192233 is not a GRB
  60. GRB 230906A: optical counterpart
  61. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 230911A: Swift-XRT afterglow detection
  63. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  64. GRB 230913A: Glowbug gamma-ray detection
  65. GRB 230812B: Bad Time Intervals for Fermi GBM data
  66. GRB 230913A: Fermi GBM Observation
  67. Swift Trigger 1191904 is not a GRB
  68. GRB 230911A: Swift ToO observations
  69. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  70. Fermi GRB 230913A: Global MASTER-Net observations report
  71. GRB 230911A: GOTO optical counterpart candidate
  72. GRB 230913A: Fermi GBM Final Real-time Localization
  73. GRB 230908A: CALET Gamma-Ray Burst Monitor detection
  74. GRB 230911D: NuSTAR Detection of Prompt Emission
  75. GRB 230911B: AstroSat CZTI detection
  76. GRB 230911C: Swift-XRT refined Analysis
  77. GRB 230911C: Swift-BAT refined analysis
  78. GRB230911C: BOOTES-6/DPRT optical upper limit
  79. GRB 230906A: Chandra detection of the X-ray afterglow
  80. Swift GRB 230911C: Global MASTER-Net observations report
  81. GRB 230911D: Fermi GBM observation
  82. IPN triangulation of GRB 230911D (long)
  83. GRB 230911D: Fermi-LAT detection
  84. GRB230911C: LCOGT Optical Upper Limits
  85. GRB 230911C: Swift/UVOT Upper Limits
  86. GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
  87. GRB 230911C: GOTO optical upper limits
  88. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  89. GRB 230911B: correction to the KW GCN 34659
  90. Konus-Wind detection of GRB 230811D
  91. GRB 230911C: Enhanced Swift-XRT position
  92. GRB 230911D: BALROG localization (Fermi Trigger 716111594/ GRB 230911329)
  93. GRB 230911D: Fermi GBM Final Localization
  94. GRB 230911C: Swift detection of a burst
  95. Fermi GRB 230911B: Global MASTER-Net observations report
  96. GRB 230911B: Fermi GBM Final Real-time Localization
  97. GRB 230911A: Fermi GBM Final Real-time Localization
  98. GRB 230906A: BlackGEM upper limits
  99. GRB 230903A: TESS observations of optical emission
  100. GRB 230906A: AstroSat CZTI detection

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