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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"

24770 results found.

  1. GRB 170113A: Swift/UVOT Observations
  2. GRB 170113A: Swift-XRT refined Analysis
  3. GRB 170113A: Fermi GBM observations
  4. GRB 170112A: Swift/UVOT Upper Limits
  5. GRB 170113A: Enhanced Swift-XRT position
  6. GRB 170113A: LCO Sutherland observations
  7. GRB 170113A: Swift detection of a burst with an optical counterpart
  8. LIGO/Virgo G268556: TZAC TAROT network observations with TRE/TCA/TCH
  9. GRB 170112A: RATIR Optical and NIR Observations
  10. GRB 170112A: Swift-BAT refined analysis
  11. GRB 161219B: afterglow and SN2016jca optical observations
  12. GRB 170111A: Swift/UVOT Upper Limits
  13. GRB 170112A: Swift-XRT observations
  14. GRB 170112A: REM optical/NIR observations
  15. GRB 170112A: Swift detection of a short burst
  16. GRB170111A: REM optical/NIR observations
  17. LIGO/Virgo G268556: Early SWASP limits of ATLAS17aeu
  18. GRB 170111A: Swift-BAT refined analysis
  19. GRB 170111A: SMARTS optical/IR observations
  20. GRB 170111A: Swift-XRT refined Analysis
  21. LIGO/Virgo G268556: Additional GROWTH follow up observation of iPTF Optical Transient Candidates
  22. GRB 161230A: POLAR Observation
  23. LIGO/Virgo G268556/GW170104: Campo Imperatore Observatory observations
  24. GRB 170111A: Enhanced Swift-XRT position
  25. GRB 170111A: Swift detection of a burst
  26. LIGO/Virgo G268556: Swift/BAT data search
  27. LIGO/Virgo G268556: Lijiang Observatory GMG Telescope Upper Limit on ATLAS17aeu
  28. LIGO/Virgo G268556: NOWT of EWE, Xinglong 0.6/0.9m, Xuyi 1m optical upper limits of ATLAS17aeu and a reminder of GCN 20394
  29. LIGO/Virgo G268556: Swift-XRT confirms that ATLAS17aeu is fading in X-rays
  30. LIGO/Virgo G268556: ATLAS17aeu position is consistent with GRB170105A
  31. LIGO/Virgo G268556/GW170104: 10.4m GTC spectroscopic observations of iPTF17fs
  32. LIGO/Virgo G268556/GW170104: TNG spectroscopic observations of iPTF17ck and iPTF17dz
  33. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  34. LIGO/Virgo G268556: Swift/UVOT observations of ATLAS17aeu
  35. LIGO/Virgo G268556: CALET Observations
  36. LIGO/Virgo G268556: AGILE-GRID preliminary analysis
  37. LIGO/Virgo G268556: EWE001 and EWE002- two events close to GCN 20382 with the skymap
  38. LIGO/Virgo G268556/GW170104: Global MASTER Net second OT detection
  39. Swift Trigger 730874 is not astrophysical
  40. LIGO/Virgo G268556: Swift-XRT detection of ATLAS17aeu
  41. GRB 170105A: AstroSat CZTI detection
  42. GRB 170105A: POLAR Observation
  43. LIGO/Virgo G268556: Updated sky map from gravitational-wave data
  44. LIGO/Virgo G268556: HAWC follow-up of northern sky
  45. LIGO/Virgo G268556: ATLAS17aeu - an unusual transient within the skymap
  46. LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
  47. Swift Trigger 730513 is not an astrophysical event
  48. LIGO/Virgo G268556: ATLAS imaging of the skymap
  49. LIGO/Virgo G268556: AGILE MCAL and Super-AGILE Observations
  50. LIGO/Virgo G268556: Fermi-LAT search for high-energy gamma-ray counterpart
  51. LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
  52. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  53. LIGO/Virgo G268556: Swift-XRT sources
  54. LIGO/Virgo G268556: ANTARES search
  55. LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
  56. GRB170104.78 MASTER-Net OT detection
  57. LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
  58. LIGO/Virgo G268556: Fermi GBM Observations
  59. GRB 170102A: POLAR observation
  60. GRB 170101B: POLAR observation
  61. GRB 161228C: POLAR observation
  62. GRS 1716-249/GRO J1719-24/V2293 Oph, Swift-BAT refined analysis
  63. GRB 170101A: POLAR observation
  64. GRB 161229A: POLAR observation
  65. GRB 170101A: Swift-BAT refined analysis
  66. GRB 170101B: Fermi GBM detection
  67. GRB161219B - Anticipated hyperluminal evidence
  68. GRB 161224A: TSHAO optical observations
  69. GRB 161224A: Swift/UVOT Upper limits
  70. GRB 161224A: Swift-XRT refined Analysis
  71. GRB 161224A: Swift-BAT refined analysis
  72. Trigger 728094, Swift-BAT refined analysis
  73. GRB 161219B: UKIRT near-IR afterglow detection
  74. GRB161219.78 MASTER-Net OT detection
  75. GRB 161219B: Rapid ALMA Observations & Detection
  76. GRB 161220A: Swift-BAT refined analysis
  77. Konus-Wind observation of GRB 161219B
  78. GRB 161219B: SALT observations
  79. GRB 161214B: optical spectroscopy of the foreground SDSS object
  80. GRB 161220A: Swift-XRT refined Analysis
  81. GRB 161220A: GROND Upper Limits
  82. GRB 161219B: ISON/Terskol optical observations
  83. GRB 161219B: Swift-BAT refined analysis
  84. GRB 161220A: Swift/UVOT Upper Limits
  85. GRB 161219B: Swift/UVOT Detection
  86. GRB 161219B: Watcher optical observations
  87. IPN Triangulation of GRB 161218B (long/very bright)
  88. GRB 161220A: Swift detection of a burst
  89. GRB 161219B: LCO Sutherland observations
  90. GRB 161219B: GROND afterglow observations
  91. GRB 161219B: Swift-XRT refined Analysis
  92. GRB 161219B: Enhanced Swift-XRT position
  93. GRB 161219B: Swift detection of a burst with an optical afterglow
  94. GRB 161219A: a long GRB detected by INTEGRAL
  95. GRB 161218A: Swift-BAT refined analysis
  96. Swift Trigger 727422 is not an astrophysical event.
  97. GRB 161218A: TAROT Calern observatory optical observations
  98. GRB 161217A: TAROT Calern observatory optical observations
  99. GRB 161218B: Fermi GBM detection
  100. GRB 161217A: MITSuME Okayama upper limits

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