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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"

32501 results found.

  1. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  2. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  3. Konus-Wind detection of GRB 230919A
  4. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  5. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  6. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  7. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  8. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  9. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  10. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  13. GRB 230918B: VLT/X-shooter classification of AT 2023tbf (GOTO23aky) as a dwarf nova
  14. IPN triangulation of GRB 230919A (short)
  15. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  16. GRB 230919A: Fermi GBM Observation
  17. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  18. Fermi GBM Statement for Trigger 716527670/230916144
  19. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  20. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  21. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  22. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  23. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  24. GRB 230919A: AstroSat CZTI detection
  25. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  26. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  27. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  28. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  29. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  30. Detection of self-absorbed radio emission from GRB 230812B with the JVLA + uGMRT
  31. GRB 230918A (short): Glowbug gamma-ray detection
  32. AT 2023sva: NOT observations of the ZTF candidate afterglow
  33. GRB 230915A: Fermi GBM observation
  34. GRB 230812B: Radio observations with the uGMRT
  35. GRB 230917A: AstroSat CZTI detection
  36. Swift Triggers 1192480, 1192481, 1192482 and 1192483 are not astrophysical events
  37. GRB 230911A: Fermi GBM Observation
  38. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  39. Fermi-LAT gamma-ray observations of IceCube-230914A
  40. GRB 230911D: GRBAlpha detection
  41. Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
  42. GRB 230906A: optical counterpart
  43. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 230911A: Swift-XRT afterglow detection
  45. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  46. GRB 230913A: Glowbug gamma-ray detection
  47. LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
  48. LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
  49. GRB 230913A: Fermi GBM Observation
  50. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  51. GRB 230911A: Swift ToO observations
  52. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  53. Fermi GRB 230913A: Global MASTER-Net observations report
  54. GRB 230911A: GOTO optical counterpart candidate
  55. GRB 230908A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 230911D: NuSTAR Detection of Prompt Emission
  57. GRB 230911B: AstroSat CZTI detection
  58. GRB 230911C: Swift-BAT refined analysis
  59. LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
  60. GRB 230906A: Chandra detection of the X-ray afterglow
  61. Swift GRB 230911C: Global MASTER-Net observations report
  62. GRB 230911D: Fermi GBM observation
  63. IPN triangulation of GRB 230911D (long)
  64. GRB 230911D: Fermi-LAT detection
  65. GRB230911C: LCOGT Optical Upper Limits
  66. LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
  67. GRB 230911C: Swift/UVOT Upper Limits
  68. GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
  69. GRB 230911C: GOTO optical upper limits
  70. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  71. GRB 230911B: correction to the KW GCN 34659
  72. Konus-Wind detection of GRB 230811D
  73. GRB 230911C: Swift detection of a burst
  74. Fermi GRB 230911B: Global MASTER-Net observations report
  75. GRB 230906A: BlackGEM upper limits
  76. GRB 230903A: TESS observations of optical emission
  77. GRB 230906A: AstroSat CZTI detection
  78. GRB 230908A: GRBAlpha detection
  79. Glowbug gamma-ray detection GRB 230905B
  80. GRB 230906A: Swift/UVOT Upper Limits
  81. GRID detection of GRB 230827A
  82. GRB 230818A: radio observation with the VLA
  83. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  84. GRB 230906A: Swift-XRT observations
  85. Konus-Wind detection of GRB 230906A (short)
  86. IPN triangulation of GRB 230906A (short)
  87. GRB 230906A: Swift ToO observations
  88. GRB 230905B: AstroSat CZTI detection
  89. Fermi GRB 230906A: Global MASTER-Net observations report
  90. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  91. LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
  92. GRB 230903A: VLT/X-shooter optical observations
  93. GRB 230903A: Swift-BAT refined analysis
  94. Fermi GRB 230903A: Global MASTER-Net observations report
  95. GRB 230903A: Fermi GBM detection
  96. GRB 230904B is not a GRB
  97. Fermi GRB 230904A: Global MASTER-Net observations report
  98. LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
  99. GRB 230903A: LCOGT Optical Upper Limits
  100. LIGO/Virgo/KAGRA S230831e: Updated Sky localization

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