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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"

5386 results found.

  1. LIGO/Virgo G211117: Subaru Hyper Suprime-Cam follow-up observation
  2. GRB 160107A: MAXI/GSC detection
  3. IPN Triangulation of GRB 151225A (short/hard)
  4. LIGO/Virgo G211117: Further Swift-XRT sources
  5. LIGO/Virgo G211117: Liverpool Telescope classification of EM candidates
  6. LIGO/Virgo G211117: Summary of Pan-STARRS transients
  7. GRB 160104B: MAXI/GSC detection
  8. LIGO/Virgo G211117: LOFAR follow-up
  9. LIGO/Virgo G211117: PESSTO classification of Pan-STARRS transients
  10. LIGO/Virgo G211117: CSS/CRTS observations on 29/30 Dec 2015 UT
  11. GRB 160102A: MAXI/GSC detection
  12. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  13. LIGO/Virgo G211117: MAXI/GSC observations
  14. LIGO/Virgo G211117: LBT Follow-up of iPTF15fen
  15. LIGO/Virgo G211117: MAGIC very-high energy gamma-ray observations
  16. LIGO/Virgo G211117: SkyMapper observations and transient candidate
  17. LIGO/Virgo G211117: Optical Observations with Kiso Schmidt telescope and KWFC
  18. LIGO/Virgo G211117: List of near-term future observation regions by Project Mini-GWAC of SVOM
  19. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  20. LIGO/Virgo G211117: La Silla - QUEST observations 2015 Dec 28, 29
  21. LIGO/Virgo G211117: Further Swift-XRT sources
  22. GRB 151228A: T60 observations
  23. LIGO/Virgo G211117: Optical NIR observation with Kanata telescope
  24. LIGO/Virgo G211117: Optical follow-up with Kanata telescope
  25. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  26. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  27. GRB 151228A: Fermi GBM observation
  28. LIGO/Virgo G211117: INAF VST-ESO PARANAL observations
  29. LIGO/Virgo G211117: Further Swift-XRT sources
  30. GRB 151228A: Swift detection of a short burst
  31. LIGO/Virgo G211117: Identification of a GW CBC Candidate
  32. GRB 151212A iTelescope observation
  33. V404Cyg Swift Trigger 668097:
  34. GRB 151216A: MAXI/GSC detection
  35. GRB151215A: Early optical light curve from pt5m, La Palma
  36. GRB 151215A: MASTER early OT detection and light curve
  37. GRB 151215A: Swift detection of a burst
  38. GRB 151212A: GROND Optical Afterglow Candidate
  39. GRB 151212A: Swift-XRT afterglow detection
  40. GRB 151212A: MAXI/GSC detection
  41. GRB 151210A: GROND Afterglow Confirmation
  42. GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
  43. GRB 151210A: Swift detection of a burst
  44. GRB 151205C: Optical follow-up observations at Kiso
  45. Swift detection of 4U 1850-03
  46. GRB 130831A: MASTER early OT detection and LC
  47. Fermi GBM trigger 470375959/151128166 is not a GRB
  48. GRB 151118A iTelescope observation
  49. GRB 151118A: Early optical limit from pt5m, La Palma
  50. GRB 151118A: ISON-NM early optical limit
  51. GRB GRB 151118A: MASTER-NET optical observations
  52. GRB 151118A: Optical observations from OSN
  53. GRB 151118A: Swift detection of a burst
  54. GRB 151114A: Swift/UVOT Detection
  55. GRB 151114A: Swift detection of a burst with an optical counterpart
  56. GRB 151112A: MAXI/GSC detection
  57. GRB 151111A: GROND marginal detection of a afterglow candidate
  58. GRB 151111A: LCOGT-FTS afterglow observations
  59. LIGO/Virgo G194575: La Silla QUEST, Pan-STARRS and PESSTO observations of iPTF15dld
  60. LIGO/Virgo G194575: VLA follow-up
  61. LIGO/Virgo G194575: INAF-TNG follow-up of iPTF15dkm and iPTF15dlj
  62. GRB 151027A: MAXI/GSC detection
  63. Konus-Wind observation of GRB 151027A
  64. GRB 151027B: VLT/X-shooter redshift
  65. LIGO/Virgo G194575: iPTF Optical Transient Candidates
  66. GRB 151027A: Early RAPTOR Observations
  67. LIGO/Virgo G194575: MASTER Optical Inspection
  68. GRB 151027A: Fermi GBM observation
  69. GRB 151027A : ISON-NM early optical detection
  70. GRB 151027A: Swift detection of a burst with a bright optical afterglow
  71. GRB 151021A: Skynet PROMPT-CTIO/DSO17 observations of the optical afterglow
  72. LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
  73. GRB 151023A
  74. LIGO/Virgo G194575: LOFAR follow-up
  75. LIGO/Virgo G184098: Further VST-ESO PARANAL observations
  76. LIGO/VIRGO G184098 : PESSTO classification of PS15cbm in the northern region
  77. LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
  78. LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
  79. IPN Triangulation of GRB 150919A (short / hard)
  80. LIGO/Virgo G184098: Pan-STARRS1 observations of the northern sky region
  81. LIGO/Virgo G184098: Observations from the TOROS collaboration
  82. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  83. LIGO/Virgo G184098: Swift follow-up observations
  84. GRB 150910A: TSHAO optical observations
  85. GRB 150915A: MASTER-NET optical observations
  86. GRB 150911A: Khureltogot upper limit
  87. GRB 150911A: WHT optical imaging
  88. GRB150911A: P60 Observations
  89. GRB150911A MITSuME Okayama Ks-band upper-limit
  90. GRB 150910A: MITSuME Okayama Ks-band Observation
  91. GRB 150910A: SAO RAS optical photometry
  92. GRB 150907B: GROND Upper Limits
  93. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  94. IPN Triangulation of GRB 150824A
  95. Swift Trigger 652824: Is most likely a noise fluctuation in the direction of M31
  96. GRB 150818A: Continued NOT monitoring - afterglow confirmation
  97. IPN Triangulation of GRB 150819B (short / very intense)
  98. GRB 150817A: LCOGT observations
  99. GRB 150817A: Swift-BAT refined analysis
  100. GRB 150817A: Enhanced Swift-XRT position

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