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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

20993 results found.

  1. GRB 170214A: Swift/UVOT Upper Limits
  2. GRB170214A: RATIR Optical and NIR Observations
  3. GRB 170209A: GROND confirmation of MASTER afterglow
  4. GRB 170214A: Swift-XRT observations
  5. GRB 170214A: Swift ToO observations
  6. GRB 170208B: SMARTS optical/IR observations
  7. GRB 170208B: IRSF upper limits
  8. GRB 170208A: IRSF upper limits
  9. GRB 170203A: 15 GHz upper limits from AMI
  10. GRB 170202A: 15 GHz upper limits from AMI
  11. GRB 170209A: Swift-XRT observations
  12. GRB 170209A: Swift ToO observations
  13. GRB 170208B: Swift/UVOT Upper Limits
  14. GRB 170208B: RATIR Optical and NIR Observations
  15. GRB 170209A: Fermi GBM Detection
  16. Correction to GCN 20640: GRB 170208B: GROND observations
  17. Fermi Trigger 508295323: MASTER-OAFA possible OT detection
  18. GRB 170208A: Swift/UVOT Upper Limits
  19. GRB 170208B: GROND observations
  20. GRB 170208B: NOT upper limits
  21. GRB 170208B: Etelman observatory optical observations
  22. GRB 170206B: Swift/UVOT Upper Limits
  23. GRB 170206A: POLAR observation
  24. GRB 170205A: Swift/UVOT Detection of a Fading Afterglow
  25. GRB 170205A: NOT afterglow observations
  26. GRB 170205A: RATIR Optical and NIR Observations
  27. GRB 170202A: SMARTS optical/IR afterglow observations
  28. GRB 170205A: LCO FTN observations
  29. GRB 170202A: SQUEAN Observation (2nd night)
  30. GRB 170202A: Zadko observatory - Gingin optical observations
  31. GRB 170202A: Etelman Observatory optical observations
  32. GRB 170202A: RATIR Optical and NIR Observations
  33. GRB 170202A: SQUEAN Observation
  34. GRB 170202A: LCO FTN observations
  35. GRB 170202A: T100 observations
  36. GRB 170202A VLT/X-shooter redshift [minor correction]
  37. GRB 170202A: Swift/UVOT Detection
  38. GRB 170202A: Redshift from OSIRIS/GTC
  39. GRB 170202A: NOT afterglow observations
  40. GRB 170202A: Kanata optical and infrared observations
  41. GRB 170202A: Zadko observatory - Gingin optical observations
  42. GRB 170202A: LCO Sutherland observations
  43. GRB 170202A : Xinglong TNT optical observation
  44. GRB 170131A: Swift/UVOT Upper Limits
  45. GRB 170131A: Swift-XRT observations
  46. GRB 170131A: Swift ToO observations
  47. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  48. GRB 170127C: Swift-XRT observations
  49. GRB 170127A: GROND Upper limits
  50. GRB 170127B: Swift/UVOT Upper Limits
  51. GRB 170127A: Swift/UVOT Upper Limits
  52. GRB 170127C: Tiled Swift observations
  53. LIGO/Virgo G270580: HAWC follow-up observations
  54. GRB 170127B: MASTER-Kislovodsk early optical observations
  55. LIGO/Virgo G270580: Swift/UVOT follow-up of PS17yt
  56. GRB 170126A: Swift/UVOT Detection of a Fading Afterglow
  57. LIGO/Virgo G270580: Fermi GBM Observations
  58. GRB 170115A: 15 GHz upper limits from AMI
  59. LIGO/Virgo G270580: MAXI/GSC observations
  60. LIGO/Virgo G270580: NOT observations of PS17yt
  61. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  62. LIGO/Virgo G270580: Asiago 1.82m observations of PS17ua and PS17yt
  63. LIGO/Virgo G270580: 10.4m GTC spectroscopic observations of PS17yt
  64. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  65. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  66. GRB 170121B: AbAO optical observations
  67. LIGO/Virgo G270580: UL50 observations
  68. GRB 170121B: MASTER early optical observations of the Swift possible XT
  69. LIGO/Virgo G270580: CALET Observations
  70. GRB 170121B: Swift-XRT and UVOT observations
  71. LIGO/Virgo G270580/GW170120 : Asiago observations
  72. GRB 170121B: LCO FTN observations
  73. LIGO/Virgo G268556/GW170104: MAXI/GSC observations
  74. GRB 170121B: Swift ToO observations
  75. LIGO/Virgo G270580: ATLAS coverage and 4 optical transients
  76. GRB 170121B/Fermi trigger 506702667 MASTER-Amur OT detection
  77. LIGO/Virgo G270580: Two optical counterpart candidates from CNEOST
  78. LIGO/Virgo G270580: INTEGRAL search of temporally coincident prompt hard X-ray
  79. LIGO/Virgo G270580: Swift-XRT sources
  80. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  81. LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
  82. LIGO/Virgo G270580: Pan-STARRS and ATLAS observations of the skymap
  83. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  84. LIGO/Virgo G270580: AGILE MCAL and Super-AGILE Observations
  85. GRB 170117A: Swift/UVOT Upper Limits
  86. GRB 170117A: Swift-XRT observations
  87. GRB 170117A: Swift ToO observations
  88. GRB 170115A: Swift/UVOT Upper Limits
  89. GRB 170115B: Swift-XRT observations
  90. LIGO/Virgo G268556: Swift-XRT observations of iPTF17cw
  91. GRB 170112A : AbAO optical observations
  92. GRB 170115B: Tiled Swift observations
  93. GRB 170113A: VLT/X-shooter redshift
  94. GRB 170113A: GROND afterglow observations
  95. GRB 170113A: Swift/UVOT Observations
  96. GRB 161214B: 15 GHz upper limits from AMI
  97. GRB 170113A: Fermi GBM observations
  98. GRB 170112A: Swift/UVOT Upper Limits
  99. GRB 170101A: 15 GHz upper limits from AMI
  100. GRB 170113A: LCO Sutherland observations

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