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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').
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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"

11778 results found.

  1. LIGO/Virgo G275404: A near-infrared transient in the error circle of AGL J1914+1043
  2. LIGO/Virgo G275697: CNEOST optical observations
  3. LIGO/Virgo G274296 and G275404 : MAXI/GSC observations
  4. LIGO/Virgo G275404: Nearby galaxy observations by J-GEM collaboration
  5. LIGO/Virgo G275404: Nearby Galaxies in the Localization Region
  6. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  7. LIGO/Virgo G275697: INTEGRAL search for a prompt gamma-ray counterpart
  8. LIGO/Virgo G275404: Fermi-LAT search for a high-energy gamma-ray counterpart
  9. LIGO/Virgo G275404: AGILE-GRID detection of a possible gamma-ray transient
  10. LIGO/Virgo G275404: SVOM/Mini-GWAC: Observations of initial skymap
  11. GRB 170220A: POLAR Observation
  12. Konus-Wind observation of GRB 170222A
  13. LIGO/Virgo G274296: CALET Observations
  14. LIGO/Virgo G274296: PS17bek is a superluminous supernova at z=0.31
  15. LIGO/Virgo G274296: J-GEM optical/NIR follow-up observations
  16. GRB 170219A: POLAR Observation
  17. Swift Trigger 739517 is probably not a GRB
  18. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  19. LIGO/Virgo G274296: PSN MASTER OT J042250.16-820415.4 is before maximum
  20. LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
  21. LIGO/Virgo G274296: Fermi-LAT search for a high-energy gamma-ray counterpart
  22. Konus-Wind observation of GRB 170219A (short/hard)
  23. IPN Triangulation of GRB 170219A (short/hard)
  24. LIGO/Virgo G274296: Optical Observation
  25. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  26. LIGO/Virgo G274296: SWASP optical imaging coverage
  27. LIGO/Virgo G274296: Observations of initial skymap by project Mini-GWAC of SVOM
  28. LIGO/Virgo G274296: REM optical/NIR observations
  29. GRB 170214A: Mondy optical upper limit
  30. Konus-Wind observation of GRB 170214A
  31. GRB 170214A: Fermi-LAT detection
  32. LIGO/Virgo G270580: DLT40 follow-up observation
  33. Konus-Wind observation of GRB 170210A
  34. GRB 170210A: POLAR observation
  35. GRB 170208C: POLAR Observation
  36. IPN Triangulation of GRB 170210A
  37. Konus-Wind observation of GRB 170209A
  38. GRB 170208B: Swift-BAT refined analysis
  39. LIGO/Virgo G270580: AstroSat CZTI upper limits
  40. GRB 170207A: POLAR Observation
  41. Konus-Wind observation of GRB 170208B
  42. Konus-Wind observation of GRB 170208A
  43. GRB 170206C: POLAR Observation
  44. GRB 170208B: Swift-XRT refined Analysis
  45. GRB 170208B: Swift detection of a burst
  46. Konus-Wind observation of GRB 170207A
  47. Konus-Wind observation of GRB 170206A
  48. GRB 170206A: POLAR observation
  49. IPN Triangulation of GRB 170206A (short/hard)
  50. GRB 170206A: Fermi-LAT detection
  51. Konus-Wind observation of GRB 170205A
  52. Konus-Wind observation of GRB 170202A
  53. GRB 170202B POLAR Observation
  54. GRB 170131A: POLAR Observation
  55. GRB 170202A: Swift-XRT refined Analysis
  56. GRB 170202A: T100 observations
  57. GRB 170131A detected in Swift/BAT ground processing
  58. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  59. GRB 170130A: POLAR Observation
  60. Konus-Wind observation of GRB 170127C (short/hard GRB with extended emission)
  61. GRB 170127B: Swift-BAT refined analysis
  62. GRB 170127C: POLAR Observation
  63. GRB 170127B: Swift-XRT refined Analysis
  64. GRB 170127A: Swift-XRT refined Analysis
  65. GRB 170124A: CALET Gamma-Ray Burst Monitor detection
  66. Konus-Wind observation of GRB 170126A
  67. GRB 170127C (Fermi/GBM trigger 507173752): AGILE analysis
  68. GRB 170127C: Fermi-LAT detection
  69. GRB 170127B: Swift detection of a short burst
  70. GRB 170126A: Swift-XRT refined Analysis
  71. LIGO/Virgo G270580: MAXI/GSC observations
  72. LIGO/Virgo G270580: No change to estimate of LIGO false alarm probability
  73. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  74. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  75. LIGO/Virgo G270580: UL50 observations
  76. GRB 170121B: MASTER early optical observations of the Swift possible XT
  77. LIGO/Virgo G270580: CALET Observations
  78. LIGO/Virgo G268556/GW170104: MAXI/GSC observations
  79. GRB 170120A: POLAR Observation
  80. LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
  81. LIGO/Virgo G270580: Two optical counterpart candidates from CNEOST
  82. LIGO/Virgo G270580: INTEGRAL search of temporally coincident prompt hard X-ray
  83. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  84. LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
  85. LIGO/Virgo G270580: Pan-STARRS and ATLAS observations of the skymap
  86. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  87. LIGO/Virgo G270580: AGILE MCAL and Super-AGILE Observations
  88. LIGO/Virgo G270580: Identification of a GW Burst Candidate
  89. Konus-Wind observation of GRB 170115B
  90. GRB 170115A: Swift-XRT refined Analysis
  91. GRB 170115B: Fermi-LAT detection
  92. GRB 170115A: Swift detection of a burst
  93. LIGO/Virgo G268556: spectra of two nuclear transients PS17fr and PS17er
  94. GRB 161219B: afterglow and SN2016jca optical observations
  95. GRB 170111A: Swift-BAT refined analysis
  96. GRB 170111A: Swift-XRT refined Analysis
  97. LIGO/Virgo G268556/GW170104: Campo Imperatore Observatory observations
  98. LIGO/Virgo G268556: AMI 15 GHz detection of ATLAS17aeu
  99. GRB 170111A: Swift detection of a burst
  100. LIGO/Virgo G268556: Spectroscopic observations of ATLAS17aeu and iPTF17cw

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