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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"

19550 results found.

  1. GRB 170127A: Swift/UVOT Upper Limits
  2. GRB 170127B: Enhanced Swift-XRT position
  3. GRB 170127B: NOT r-band upper limits
  4. GRB 170127A: Enhanced Swift-XRT position
  5. GRB 170127C: Tiled Swift observations
  6. GRB 170127C: Fermi-LAT detection
  7. LIGO/Virgo G270580: HAWC follow-up observations
  8. GRB 170127B: Swift detection of a short burst
  9. GRB 170127A: Swift detection of a burst
  10. GRB 170126A: Swift/UVOT Detection of a Fading Afterglow
  11. GRB 170126A: Enhanced Swift-XRT position
  12. GRB 170126A: Swift detection of a burst with an optical counterpart
  13. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  14. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  15. GRB 170121B: AbAO optical observations
  16. LIGO/Virgo G270580: CALET Observations
  17. GRB 170121B: Swift-XRT and UVOT observations
  18. GRB 170121B: Swift ToO observations
  19. LIGO/Virgo G270580: ATLAS coverage and 4 optical transients
  20. LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
  21. LIGO/Virgo G270580: Two optical counterpart candidates from CNEOST
  22. LIGO/Virgo G270580: Swift/BAT data search
  23. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  24. LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
  25. LIGO/Virgo G270580: Pan-STARRS and ATLAS observations of the skymap
  26. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  27. LIGO/Virgo G270580: AGILE MCAL and Super-AGILE Observations
  28. LIGO/Virgo G270580 ANTARES search
  29. GRB 170117A: Swift/UVOT Upper Limits
  30. GRB 170117A: Swift-XRT observations
  31. GRB 170117A: Swift ToO observations
  32. GRB 170115A : AbAO optical upper limit
  33. GRB 170115A: Swift/UVOT Upper Limits
  34. GRB 170112A : AbAO optical observations
  35. GRB 170115B: Tiled Swift observations
  36. GRB 170115A: Enhanced Swift-XRT position
  37. GRB 170115A: Swift detection of a burst
  38. GRB 170113A: GROND afterglow observations
  39. GRB 170113A: Swift/UVOT Observations
  40. GRB 170112A: Swift/UVOT Upper Limits
  41. GRB 170113A: Enhanced Swift-XRT position
  42. GRB 170113A: Swift detection of a burst with an optical counterpart
  43. LIGO/Virgo G268556: TZAC TAROT network observations with TRE/TCA/TCH
  44. GRB 170112A: RATIR Optical and NIR Observations
  45. GRB 170112A: Swift-BAT refined analysis
  46. GRB 161219B: afterglow and SN2016jca optical observations
  47. GRB 170111A: Swift/UVOT Upper Limits
  48. GRB 170112A: Swift-XRT observations
  49. GRB 170112A: REM optical/NIR observations
  50. GRB 170112A: Swift detection of a short burst
  51. GRB170111A: REM optical/NIR observations
  52. LIGO/Virgo G268556: Early SWASP limits of ATLAS17aeu
  53. LIGO/Virgo G268556: Additional GROWTH follow up observation of iPTF Optical Transient Candidates
  54. GRB 170111A: Enhanced Swift-XRT position
  55. GRB 170111A: Swift detection of a burst
  56. LIGO/Virgo G268556: Swift/BAT data search
  57. LIGO/Virgo G268556: Lijiang Observatory GMG Telescope Upper Limit on ATLAS17aeu
  58. LIGO/Virgo G268556: NOWT of EWE, Xinglong 0.6/0.9m, Xuyi 1m optical upper limits of ATLAS17aeu and a reminder of GCN 20394
  59. LIGO/Virgo G268556/GW170104: TNG observations of ATLAS17aeu
  60. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  61. LIGO/Virgo G268556: GWAC_F60B (60cm) follow-up two events of EWE001 and EWE002
  62. LIGO/Virgo G268556: Swift/UVOT observations of ATLAS17aeu
  63. LIGO/Virgo G268556: CALET Observations
  64. LIGO/Virgo G268556: EWE001 and EWE002- two events close to GCN 20382 with the skymap
  65. LIGO/Virgo G268556/GW170104: Global MASTER Net second OT detection
  66. Swift Trigger 730874 is not astrophysical
  67. LIGO/Virgo G268556: HAWC follow-up of northern sky
  68. LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
  69. Swift Trigger 730513 is not an astrophysical event
  70. LIGO/Virgo G268556: ATLAS imaging of the skymap
  71. LIGO/Virgo G268556: AGILE MCAL and Super-AGILE Observations
  72. LIGO/Virgo G268556: Fermi-LAT search for high-energy gamma-ray counterpart
  73. LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
  74. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  75. LIGO/Virgo G268556: ANTARES search
  76. LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
  77. LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
  78. LIGO/Virgo G268556: Fermi GBM Observations
  79. GRS 1716-249/GRO J1719-24/V2293 Oph, Swift-BAT refined analysis
  80. GRB 170101A: Swift-BAT refined analysis
  81. GRB 170101B: Astrosat CZTI detection
  82. GRB 161224A: TSHAO optical observations
  83. GRB 161224A: Swift/UVOT Upper limits
  84. GRB 161224A: Swift-XRT refined Analysis
  85. Trigger 728094, Swift-BAT refined analysis
  86. GRB 161219B: UKIRT near-IR afterglow detection
  87. GRB 161219B: SALT observations
  88. GRB 161220A: GROND Upper Limits
  89. GRB 161219B: ISON/Terskol optical observations
  90. GRB 161219B: Swift-BAT refined analysis
  91. GRB 161220A: Swift/UVOT Upper Limits
  92. GRB 161219B: Swift/UVOT Detection
  93. GRB 161219B: Watcher optical observations
  94. Konus-Wind observation of GRB 161218B
  95. IPN Triangulation of GRB 161218B (long/very bright)
  96. GRB 161220A: Swift detection of a burst
  97. GRB 161219B: GROND afterglow observations
  98. GRB 161219B: Enhanced Swift-XRT position
  99. GRB 161219B: Swift detection of a burst with an optical afterglow
  100. Konus-Wind observation of GRB 161218A

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