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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"

19572 results found.

  1. GRB 170205A: RATIR Optical and NIR Observations
  2. GRB 170202A: SMARTS optical/IR afterglow observations
  3. GRB 170205A: Swift detection of a burst with an optical counterpart
  4. GRB 170202A: Zadko observatory - Gingin optical observations
  5. GRB 170202A: Etelman Observatory optical observations
  6. GRB 170202A: RATIR Optical and NIR Observations
  7. GRB 170202A: SQUEAN Observation
  8. GRB 170202A: T100 observations
  9. GRB 170202A: Swift/UVOT Detection
  10. GRB 170202A: Enhanced Swift-XRT position
  11. GRB 170202A: NOT afterglow observations
  12. GRB 170202A: Zadko observatory - Gingin optical observations
  13. GRB 170202A: MASTGlobal ER-Net bright OT nonmonotonic light curve
  14. GRB 170202A: Mini-MegaTORTORA upper limits
  15. GRB 170202A: Swift detection of a burst with an optical afterglow
  16. GRB 170131A: Swift/UVOT Upper Limits
  17. GRB 170131A: Swift ToO observations
  18. GRB 170127B: Swift-BAT refined analysis
  19. GRB 170127C: Swift-XRT observations
  20. GRB 170127A: GROND Upper limits
  21. GRB 170124A: CALET Gamma-Ray Burst Monitor detection
  22. GRB 170127B: Swift/UVOT Upper Limits
  23. GRB 170127A: Swift/UVOT Upper Limits
  24. GRB 170127B: Enhanced Swift-XRT position
  25. GRB 170127B: NOT r-band upper limits
  26. GRB 170127A: Enhanced Swift-XRT position
  27. GRB 170127C: Tiled Swift observations
  28. GRB 170127C: Fermi-LAT detection
  29. LIGO/Virgo G270580: HAWC follow-up observations
  30. GRB 170127B: Swift detection of a short burst
  31. GRB 170127A: Swift detection of a burst
  32. GRB 170126A: Swift/UVOT Detection of a Fading Afterglow
  33. GRB 170126A: Enhanced Swift-XRT position
  34. GRB 170126A: Swift detection of a burst with an optical counterpart
  35. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  36. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  37. GRB 170121B: AbAO optical observations
  38. LIGO/Virgo G270580: CALET Observations
  39. GRB 170121B: Swift-XRT and UVOT observations
  40. GRB 170121B: Swift ToO observations
  41. LIGO/Virgo G270580: ATLAS coverage and 4 optical transients
  42. LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
  43. LIGO/Virgo G270580: Two optical counterpart candidates from CNEOST
  44. LIGO/Virgo G270580: Swift/BAT data search
  45. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  46. LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
  47. LIGO/Virgo G270580: Pan-STARRS and ATLAS observations of the skymap
  48. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  49. LIGO/Virgo G270580: AGILE MCAL and Super-AGILE Observations
  50. LIGO/Virgo G270580 ANTARES search
  51. GRB 170117A: Swift/UVOT Upper Limits
  52. GRB 170117A: Swift-XRT observations
  53. GRB 170117A: Swift ToO observations
  54. GRB 170115A : AbAO optical upper limit
  55. GRB 170115A: Swift/UVOT Upper Limits
  56. GRB 170112A : AbAO optical observations
  57. GRB 170115B: Tiled Swift observations
  58. GRB 170115A: Enhanced Swift-XRT position
  59. GRB 170115A: Swift detection of a burst
  60. GRB 170113A: GROND afterglow observations
  61. GRB 170113A: Swift/UVOT Observations
  62. GRB 170112A: Swift/UVOT Upper Limits
  63. GRB 170113A: Enhanced Swift-XRT position
  64. GRB 170113A: Swift detection of a burst with an optical counterpart
  65. LIGO/Virgo G268556: TZAC TAROT network observations with TRE/TCA/TCH
  66. GRB 170112A: RATIR Optical and NIR Observations
  67. GRB 170112A: Swift-BAT refined analysis
  68. GRB 161219B: afterglow and SN2016jca optical observations
  69. GRB 170111A: Swift/UVOT Upper Limits
  70. GRB 170112A: Swift-XRT observations
  71. GRB 170112A: REM optical/NIR observations
  72. GRB 170112A: Swift detection of a short burst
  73. GRB170111A: REM optical/NIR observations
  74. LIGO/Virgo G268556: Early SWASP limits of ATLAS17aeu
  75. LIGO/Virgo G268556: Additional GROWTH follow up observation of iPTF Optical Transient Candidates
  76. GRB 170111A: Enhanced Swift-XRT position
  77. GRB 170111A: Swift detection of a burst
  78. LIGO/Virgo G268556: Swift/BAT data search
  79. LIGO/Virgo G268556: Lijiang Observatory GMG Telescope Upper Limit on ATLAS17aeu
  80. LIGO/Virgo G268556: NOWT of EWE, Xinglong 0.6/0.9m, Xuyi 1m optical upper limits of ATLAS17aeu and a reminder of GCN 20394
  81. LIGO/Virgo G268556/GW170104: TNG observations of ATLAS17aeu
  82. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  83. LIGO/Virgo G268556: GWAC_F60B (60cm) follow-up two events of EWE001 and EWE002
  84. LIGO/Virgo G268556: Swift/UVOT observations of ATLAS17aeu
  85. LIGO/Virgo G268556: CALET Observations
  86. LIGO/Virgo G268556: EWE001 and EWE002- two events close to GCN 20382 with the skymap
  87. LIGO/Virgo G268556/GW170104: Global MASTER Net second OT detection
  88. Swift Trigger 730874 is not astrophysical
  89. LIGO/Virgo G268556: HAWC follow-up of northern sky
  90. LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
  91. Swift Trigger 730513 is not an astrophysical event
  92. LIGO/Virgo G268556: ATLAS imaging of the skymap
  93. LIGO/Virgo G268556: AGILE MCAL and Super-AGILE Observations
  94. LIGO/Virgo G268556: Fermi-LAT search for high-energy gamma-ray counterpart
  95. LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
  96. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  97. LIGO/Virgo G268556: ANTARES search
  98. LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
  99. LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
  100. LIGO/Virgo G268556: Fermi GBM Observations

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