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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"

20542 results found.

  1. LIGO/Virgo G288732:SVOM/Mini-GWAC observations of the initial skymap
  2. LIGO/Virgo G288732: AGILE GRID Observations
  3. LIGO/Virgo G288732: Fermi-LAT detection of a weak candidate
  4. LIGO/Virgo G288732: IceCube neutrino observations update
  5. GRB 170607A: Correction on the possible host galaxy identification
  6. LIGO/Virgo G288732: AGILE MCAL Observations
  7. LIGO/VIRGO G288732: Fermi GBM Observations
  8. GRB 170607A: Swift/UVOT Detection
  9. GRB 170607A: MASTER-Tavrida early OT observations
  10. GRB 170607A: NOT optical afterglow detection
  11. GRB 170526A: 15 GHz upper limits from AMI
  12. GRB 170524A: 15 GHz upper limits from AMI
  13. GRB 170519A: 15 GHz upper limits from AMI
  14. GRB 170531B: Zeiss-1000/CrAO optical observations
  15. GRB 170519A: TShAO and AbAO optical observations
  16. GRB 170604A: Swift/UVOT Observations
  17. GRB 170519A: Mondy optical observations
  18. GRB 170604A: RATIR Optical and NIR Observations
  19. GRB 170604A: AbAO optical observations
  20. GRB 170522A: confirmation of the X-ray afterglow
  21. GROND observations of GRB170604A
  22. Swift Trigger 755873: MASTER Net optical observations
  23. GRB 170604A: GTC spectroscopic redshift
  24. Swift Trigger 755873: D50 optical limits
  25. GRB 170604A: optical observations
  26. Trigger 755848: Swift spurious trigger on Cen X-3
  27. GRB 170531B: ISON/Terskol optical observations
  28. GRB 170531B: Swift/UVOT Detection
  29. GRB 170531B: SMARTS optical/IR observations
  30. GRB 170531A: Swift/UVOT Upper Limits
  31. GRB 170531B: LCO observations
  32. GRB 170531A: MASTER Net job
  33. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  34. GROND observations of GRB 170531B
  35. GRB 170531B: Redshift from GTC/OSIRIS
  36. GRB 170531A: ePESSTO NTT observations
  37. GRB 170531B: MASTER Net OT detection
  38. GRB 170531A: Swift/UVOT Observations
  39. GRB 170519A: CrAO optical observations
  40. GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
  41. GRB 170519A: ISON/Multa optical observations
  42. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  43. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  44. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  45. GRB 170526A: Swift/UVOT Upper Limits
  46. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  47. GRB 170524A: RATIR Optical and NIR Observations
  48. GRB 170524B: Swift-XRT observations
  49. GRB 170524B: MASTER-OAFA observations
  50. GRB 170524A: TSHAO and CrAO optical observations
  51. GRB 170524B: Swift ToO observations
  52. GRB 170524A: Swift/UVOT Upper Limits
  53. GRB 170524A: D50 optical observation and limit
  54. GRB 170522A: LCO McDonald observations
  55. GRB 170522A: Swift-XRT observations
  56. GRB 170522A: Global MASTER-Net job
  57. GRB 170522A: Tiled Swift observations
  58. GRB 170519A: Watcher optical observations
  59. GRB 170519A: Continued RATIR Optical and NIR Observations
  60. GRB 170519A: NOT optical observations
  61. GRB170519A, Swift-UVOT Detection
  62. GRB 170519A: KAIT Optical Observations
  63. GRB 170519A: iTelescope T11 optical observations
  64. GRB 170519A: Weihai optical observations
  65. GRB 170510A: LCO Siding Springs early observations
  66. GRB 170519A: RATIR Optical and NIR Observations
  67. GRB 170519A: optical observations
  68. GRB 170510A: Swift-XRT afterglow detection
  69. GRB 170516A: Swift/UVOT Upper Limits
  70. Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
  71. Swift Trigger on AXP CXOU J164710.2-455216
  72. GRB 170510A: Global MASTER Net possible OT observations
  73. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  74. LIGO/Virgo G284239: Konus-Wind observations
  75. GRB 170510A: LCO possible counterpart
  76. GRB 170510A: Swift-XRT observations
  77. LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
  78. LIGO/Virgo G284239: MAXI/GSC observations
  79. GRB 170510A: Tiled Swift observations
  80. GRB 170423A: TAROT Reunion observatory optical observations
  81. Swift XRT observations of GRB 170424A
  82. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  83. LIGO/Virgo G284239: HAWC follow-up
  84. LIGO/Virgo G284239: MASTER automatic follow up and synchronous observations
  85. LIGO/Virgo G284239: TZAC TAROT network observations with TRE/TCA/TCH
  86. LIGO/Virgo G284239: AGILE GRID observations
  87. LIGO/Virgo G284239: INTEGRAL search for a prompt gamma-ray counterpart
  88. LIGO/Virgo G284239: AGILE MCAL Observations
  89. LIGO/Virgo G284239: IceCube neutrino observations
  90. GRB 170428A: GTC spectroscopic redshift of candidate host galaxy
  91. GRB 170428A: 15 GHz upper limits from AMI
  92. Swift Trigger 748858: 15 GHz upper limits from AMI
  93. GRB 170428A: TNG optical observations
  94. Short GRB 170428A: MASTER-OAFA final reduction of the optical observations
  95. GRB 170428A: DCT Imaging
  96. GRB 170428A: TAROT La Silla observatory optical observations
  97. GRB 170428A: RATIR Afterglow Confirmation
  98. GRB 170428A: GROND detection of the afterglow
  99. GRB 170428A: Swift/UVOT Upper Limits
  100. GRB 170428A: Xinglong 2.16-m upper limit and host galaxy candidate

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