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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"

4738 results found.

  1. LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
  2. LIGO/Virgo G299232: LOFAR follow-up
  3. GRB 170903A: UAFO /ISON optical upper limit
  4. GRB 170903A: MITSuME Okayama upper limits
  5. GRB 170903A: Nanshan optical upper limit
  6. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  7. GRB 170830A: Fermi GBM observation
  8. GRB 170830A: Astrosat CZTI detection
  9. GRB 170830A: MAXI/GSC detection
  10. LIGO/Virgo G299232: Liverpool Telescope observations
  11. LIGO/Virgo G299232: COATLI Observations of MASTER OT J033744.97+723159.0
  12. LIGO/Virgo G299232 : MAXI/GSC observations
  13. IPN Triangulation of GRB 170826A (short)
  14. LIGO/Virgo G299232 TZAC/TAROT observations
  15. LIGO/Virgo G298936 TAROT/TZAC observations
  16. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  17. LIGO/Virgo G298936: GWFUNC/CNEOST optical observations and an optical transient
  18. GRB 170823A: Swift detection of a burst
  19. LIGO/Virgo G298048: ATCA 8.5 GHz observations of galaxies in the localisation volume
  20. LIGO/Virgo G298048: TOROS optical counterpart search
  21. LIGO/Virgo G298048: HSC observations of the OT candidate of G298048
  22. GRB 170818A: Fermi GBM detection
  23. LIGO/Virgo G298048: Subaru HSC follow-up observations
  24. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume
  25. LIGO/Virgo G297595: Swift-XRT sources
  26. LIGO/Virgo G297595: MASTER MASTER Bright PSN detection in error-box
  27. LIGO/Virgo G297595: INAF VST-ESO PARANAL observations
  28. LIGO/Virgo G297595: Subaru Hyper Suprime-Cam follow-up observations
  29. LIGO/Virgo G297595: REM optical/NIR observations
  30. GRB 170810A: VLA Detection
  31. LIGO/Virgo G296853: Liverpool Telescope classification of MASTER OT J013646.48-140323.5
  32. GRB 170810A: Swift/UVOT Detection
  33. GRB 170810A: Swift detection of a burst with a bright optical counterpart
  34. GRB 170808A: MAXI/GSC detection
  35. GRB 170807A: Swift detection of a burst
  36. GRB 170804A: Swift detection of a burst with optical counterpart
  37. Swift Trigger 765783 is not an astrophysical event.
  38. GRB 170728B: time correction to MASTER GCN Circular 21391
  39. Konus-Wind observation of GRB 170728B
  40. GRB 170726A: AstroSat CZTI detection
  41. GRB 170728B: BOOTES-2/TELMA optical detection during the extended gamma-ray phase
  42. GRB 170728B iTelescope observation
  43. GRB 170728A: Swift/UVOT Detection
  44. GRB 170728B: Fermi GBM detection
  45. GRB 170728B: Swift detection of a short burst
  46. GRB 170714A: TNG NIR observations
  47. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  48. GRB 170712A: AstroSat CZTI detection
  49. GRB 170711A: ISON/Terskol and AbAO optical observations
  50. GRB 170711A: Prompt enhanced Swift-XRT position
  51. Correction to GCN Circular 21305: Trigger 760835: Swift misidentification of GRS1716-249
  52. Trigger 760835: Swift misidentification of GRS1716-249
  53. GRB 170705A: MASTER-OAFA early OT observations
  54. LIGO/Virgo G288732: Pan-STARRS coverage of the Fermi/LAT candidate position
  55. GRB 170610A: MAXI/GSC detection
  56. LIGO/Virgo G288732: Swift-XRT follow up of the putative LAT counterpart
  57. LIGO/Virgo G288732:SVOM/Mini-GWAC observations of the initial skymap
  58. GRB 170607A: MASTER-Tavrida early OT observations
  59. GRB 170531A: MASTER Net job
  60. GROND observations of GRB 170531B
  61. GRB 170531B: Redshift from GTC/OSIRIS
  62. GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
  63. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  64. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  65. GRB 170524B: Swift-XRT observations
  66. GRB 170522A: LCO McDonald observations
  67. GRB 170519A: MITSuME Akeno Optical Observation
  68. GRB 170519A: MITSuME Okayama Optical Observation
  69. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  70. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  71. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  72. LIGO/Virgo G284239: MASTER automatic follow up and synchronous observations
  73. GRB 170428A: TNG optical observations
  74. GRB 170428A: Swift detection of a short burst
  75. Swift Trigger 748858: AbAO and TSHAO optical observations
  76. GRB 170317A: SAO RAS optical observations
  77. Trigger 745966: Swift detection of 4U1850-03
  78. GRB 170325A: optical observations, possible OT/host detection
  79. IceCube-170321A: Konus-Wind upper limits
  80. Fermi-LAT Gamma-ray Observations of IceCube-170321
  81. DOAO 1m telescope V, R, I observation of GRB 170317A
  82. IceCube-170321A: Swift-XRT observations
  83. LIGO/Virgo G275697: LOFAR follow-up
  84. GRB 170331A: LCO Sutherland observations
  85. Fermi trigger 512347439/GRB 170327A: MASTER-SAAO possible OT detection
  86. GRB 170325B: POLAR Observation
  87. LIGO/Virgo G277583: Konus-Wind observations
  88. GRB 170325A, Swift-BAT detection of a short GRB
  89. INTEGRAL pointed follow-up of IceCube-170321A
  90. Konus-Wind observation of GRB 170320A
  91. GRB 170320A: POLAR Observation
  92. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  93. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  94. INTEGRAL SPI-ACS observation of AMON IceCube EHE 80305071 129307
  95. IPN Triangulation of GRB 170320A (long/intense)
  96. GRB 170317A: Mondy optical observations
  97. GRB 170317A: POLAR observation
  98. GRB 170318B: RATIR Optical and NIR Observations
  99. GRB 170317A: RATIR Optical and NIR Observations
  100. GRB 170318A: RATIR Optical and NIR Observations

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