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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"

3850 results found.

  1. LIGO/Virgo G299232: SVOM/2.16-m Optical Telescope Observations of Swift UVOT Transient
  2. GRB 170830A: MAXI/GSC detection
  3. LIGO/Virgo G299232: WHT non-detection u-band optical transient
  4. LIGO/Virgo G299232: Liverpool Telescope observations
  5. LIGO/Virgo G299232/PGWB170825.55: early MASTER observations of the Swift UVOT source position
  6. LIGO/Virgo G296853: PIRATE observations
  7. GRB170827A: Further GROND follow-up observations
  8. LIGO/Virgo G299232 TZAC/TAROT observations
  9. LIGO/Virgo G298936: Astrosat CZTI upper limits
  10. LIGO/Virgo G299232: Astrosat CZTI upper limits
  11. LIGO/Virgo G298936 TAROT/TZAC observations
  12. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  13. LIGO/Virgo G298389 : MAXI/GSC observations
  14. LIGO/Virgo G298048: HSC observations of the OT candidate of G298048
  15. LIGO/Virgo G298048: TZAC TAROT Reunion (TRE) observations
  16. LIGO/Virgo G298048: REM optical/NIR observations
  17. LIGO/Virgo G298048: Subaru HSC follow-up observations
  18. LIGO/Virgo G298048: REM optical/NIR observations of candidate in NGC 4993
  19. LIGO/Virgo G298048: Potential host galaxies from the GLADE catalog
  20. LIGO/Virgo G298048: Astrosat CZTI upper limits
  21. LIGO/Virgo G296853 TZAC TAROT observations
  22. LIGO/Virgo G297595: MASTER MASTER Bright PSN detection in error-box
  23. LIGO/Virgo G297595: Subaru Hyper Suprime-Cam follow-up observations
  24. LIGO/Virgo G297595: REM optical/NIR observations
  25. GRB 170813A: Enhanced Swift-XRT position
  26. GRB 170813A: Swift detection of a burst
  27. Konus-Wind observation of GRB 170808B
  28. GRB 170808A: MAXI/GSC detection
  29. GRB 170728B: TShAO, SAO RAS and AbAO optical observations
  30. GRB 170728B: MASTER-IAC first minute short GRB early OT detection
  31. GRB 170728B: COATLI Observations And Confirmation of Fading
  32. GRB 170728B iTelescope observation
  33. GRB 170728B: NOT optical afterglow confirmation
  34. Fermi GBM trigger 522048561/170718229 is not a GRB
  35. LIGO/Virgo G275697: LOFAR follow-up
  36. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  37. GRB 170705A: TShAO optical observations
  38. GRB 170710A: Gemini-S candidate counterpart
  39. GRB 170710A: Enhanced Swift-XRT position
  40. GRB 170710A: Prompt enhanced Swift-XRT position
  41. GRB 170710A: Swift detection of a burst
  42. GRB 170705A: MITSuME Akeno Optical Observation
  43. GRB 170629A: Fermi GBM observation
  44. LIGO/Virgo G288732: Swift-XRT follow up of the putative LAT counterpart
  45. GRB 170607A: Swift/UVOT Detection
  46. GRB 170607A: Swift detection of a burst with a bright optical counterpart
  47. GRB 170531B: Redshift from GTC/OSIRIS
  48. GRB 170524A: Swift detection of a burst (or possible new SGR)
  49. GRB 170522A: Swift-XRT observations
  50. Konus-Wind observation of GRB 170510A
  51. LIGO/Virgo G284239: AstroSat CZTI upper limits
  52. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  53. LIGO/Virgo G284239: TZAC TAROT network observations with TRE/TCA/TCH
  54. GRB 170428A: DCT Imaging
  55. Swift Trigger 748858: AbAO and TSHAO optical observations
  56. GRB 170419B: Swift detection of a burst
  57. Swift Trigger 748858: MASTER-OAFA early optical observations
  58. Konus-Wind observation of GRB 170409A
  59. Trigger 745966: Swift detection of 4U1850-03
  60. GRB 170325A: optical observations, possible OT/host detection
  61. Swift triggered on SAX J1806.5-221
  62. LIGO/Virgo G275697: LOFAR follow-up
  63. GRB 170330A: Swift detection of a burst
  64. GRB 170329A: Fermi GBM detection
  65. GRB 170329A: Fermi-LAT detection
  66. INTEGRAL pointed follow-up of IceCube-170321A
  67. Konus-Wind observation of GRB 170320A
  68. GRB 170318B: Swift detection of a burst
  69. LIGO/Virgo G277583: AstroSat CZTI upper limits
  70. GRB 170317A: Swift/UVOT Detection
  71. GRB 170317A: Enhanced Swift-XRT position
  72. GRB 170317A: Swift detection of a burst with an optical counterpart
  73. LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
  74. LIGO/Virgo G277583: TAROT Calern (TCA) observations
  75. LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
  76. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  77. GRB 170306A, Swift-BAT refined analysis
  78. GRB 170306A: Swift-XRT refined Analysis
  79. LIGO/Virgo G275697: Further Swift-XRT sources
  80. LIGO/Virgo G275697: AstroSat CZTI upper limits
  81. LIGO/Virgo G275697: SVOM/Mini-GWAC observations of the initial skymap
  82. LIGO/Virgo G275404: iPTF Optical Transient Candidates
  83. LIGO/Virgo G275697: CNEOST optical observations
  84. LIGO/Virgo G275404: Nearby galaxy observations by J-GEM collaboration
  85. LIGO/Virgo G275697: INTEGRAL search for a prompt gamma-ray counterpart
  86. LIGO/Virgo G275404: AstroSat CZTI upper limits
  87. LIGO/Virgo G275404: SVOM/Mini-GWAC: Observations of initial skymap
  88. LIGO/Virgo G274296: J-GEM optical/NIR follow-up observations
  89. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  90. LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
  91. LIGO/Virgo G274296: AstroSat CZTI upper limits
  92. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  93. LIGO/Virgo G274296: Observations of initial skymap by project Mini-GWAC of SVOM
  94. GRB 170214A: Fermi GBM detection
  95. IPN Triangulation of GRB 170209A
  96. LIGO/Virgo G270580: AstroSat CZTI upper limits
  97. LIGO/Virgo G270580: Gemini-South Spectroscopic Classification of Optical Transients
  98. Konus-Wind observation of GRB 170206A
  99. GRB 170202A: MITSuME Akeno Optical Observation
  100. GRB 170202A: MASTGlobal ER-Net bright OT nonmonotonic light curve

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