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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"

7445 results found.

  1. Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration
  2. GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
  3. GRB 171102B: Swift detection of a burst
  4. GRB 171030A: Swift ToO observations
  5. Fermi-GBM triggers due to Swift J0243.6+6124
  6. AMI-LA observations of the new Be X-ray binary Swift J0243.6+6124
  7. Swift Trigger 783893 is probably not a GRB
  8. Retraction of high energy neutrino candidate IceCube-171028
  9. GRB 171027A: VLT optical upper limits
  10. GRB 171027A: LCO 1-m telescope observations
  11. GRB 171027A: RATIR Detection of a NIR Afterglow Candidate
  12. GRB 171027A: Swift detection of a burst
  13. Numerous Fermi-GBM Subthreshold Notices are due to Swift J0243.6+6
  14. GRB 171020A: Swift detection of a burst
  15. Search for counterpart to IceCube-171015A with ANTARES
  16. INTEGRAL SPI-ACS observation of IceCube-171015A
  17. Swift trigger 779171 is probably a noise fluctuation
  18. IceCube-171015A - IceCube observation of a high-energy neutrino candidate event
  19. GRB 171010A : Optical observations from HCT
  20. GRB 171010A: RATIR Optical and NIR Observations
  21. GRB 171013A: Swift detection of a possible burst
  22. GRB 171010B: Swift ToO observations
  23. GRB 171010A: optical observations
  24. GRB 171010A: Swift ToO observations
  25. LIGO/Virgo G298048/GW170817: updated localization from parameter estimation
  26. GRB 171007A: Swift detection of a burst
  27. GRB 171004A: Swift detection of a burst
  28. LIGO/Virgo G299232: LOFAR follow-up
  29. GRB 171003A: Swift detection of a burst or a Galactic Transient
  30. GRB 171001A: Swift detection of a burst
  31. 3.6m Devasthal Optical Telescope observations of GRB 170428A
  32. LIGO/Virgo G297595/GW170814: updated localization from parameter estimation
  33. LIGO/Virgo G298048: Summary of Pi of the Sky observations
  34. Search for counterpart to IceCube-170922A with ANTARES
  35. INTEGRAL SPI-ACS observation of AMON IceCube-170922A
  36. IceCube-170922A - IceCube observation of a high-energy neutrino candidate event
  37. GRB 170921A: Swift detection of a burst
  38. Swift trigger 773082 is probably not astrophysical
  39. LIGO/Virgo G297595: PIRATE observations
  40. LIGO/Virgo G299232: Khureltogot observations
  41. LIGO/Virgo G299232: Pierre Auger Observatory follow-up
  42. LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
  43. GRB 170912B: Swift detection of a burst
  44. GRB 170912A: Swift detection of a burst
  45. GRB 170906B: Swift detection of a burst
  46. GRB 170906A: Swift detection of a burst with an optical afterglow
  47. LIGO/Virgo G298389: Fermi GBM Flux Upper Limits
  48. LIGO/Virgo G299232: LOFAR follow-up
  49. Swift Triggers on MAXI J1535-571
  50. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  51. GRB 170902A: Swift detection of a burst or possible Galactic transient
  52. LIGO/Virgo G298936: PIRATE observations
  53. LIGO/Virgo G299232 ANTARES search (2)
  54. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  55. LIGO/Virgo G298048: OVRO 40m telescope follow-up
  56. LIGO/Virgo G298936: Updated localization from parameter estimation on LIGO and Virgo data
  57. LIGO/Virgo G296853: PIRATE observations
  58. LIGO/Virgo G298048: ALMA observations
  59. LIGO/Virgo G298048: Zadko Telescope 7 day observations of the OT candidate SSS17a/DLT17ck
  60. LIGO/Virgo G298936: HAWC follow-up
  61. LIGO/Virgo G299232 TZAC/TAROT observations
  62. GROND observations of GRB170827A
  63. GRB 170827A: ePESSTO NTT afterglow candidate
  64. LIGO/Virgo G299232: Transient near NGC 1343 has a somewhat blue r-i color
  65. GRB 170827A: REM optical/NIR observations
  66. LIGO/Virgo G299232: Astrosat CZTI upper limits
  67. LIGO/VIRGO G299232: Fermi GBM Observations
  68. LIGO/Virgo G299232 : Fermi-LAT search for high-energy gamma-ray counterpart
  69. LIGO/Virgo G299232: AGILE MCAL detection of a short gamma-ray candidate
  70. LIGO/Virgo G299232: INTEGRAL search for a prompt gamma-ray counterpart
  71. LIGO/Virgo G299232: COINCIDENT IceCube neutrino observation UPDATE
  72. LIGO/Virgo G299232 ANTARES search
  73. LIGO/Virgo G297595: INTEGRAL pointed follow-up observations
  74. LIGO/Virgo G299232: FOUND COINCIDENT IceCube neutrino observation
  75. LIGO/Virgo G299232: Identification of a GW Compact Binary Coalescence Candidate
  76. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  77. LIGO/Virgo G298048: Pierre Auger Observatory neutrino follow-up
  78. LIGO/Virgo G298048: Subaru HSC z-band imaging of the OT candidate SSS17a
  79. LIGO/Virgo G298048: HAWC follow-up
  80. LIGO/Virgo G298048: MUSE Integral Field Observations
  81. LIGO/VIRGO G298048: AAT/AAO spectroscopic observations of the GW counterpart candidate SSS17a/DLT17ck
  82. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  83. LIGO/Virgo G298048: Properties of NGC 4993
  84. LIGO/Virgo G298936 : Fermi-LAT search for a high-energy gamma-ray counterpart
  85. LIGO/Virgo G298048: Continued VLA monitoring at 6 GHz
  86. LIGO/VIRGO G298936: Fermi GBM Observations
  87. LIGO/Virgo G298936: Updated localization from gravitational-wave data
  88. LIGO/Virgo G298936 ANTARES search
  89. LIGO/Virgo G298936: IceCube neutrino observations
  90. LIGO/Virgo G298936: Identification of a GW Binary Black Hole Candidate
  91. GRB 170822A: AbAO optical upper limit
  92. LIGO/Virgo G298048: Global properties and star-formation rate of NGC 4993
  93. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  94. GRB 170822A:BOOTES-5/JGT optical afterglow candidate
  95. GRB 170822A: Swift detection of a burst
  96. LIGO/Virgo G298048: ASKAP observations of SSS17a and NGC 4993 at 1.345 GHz
  97. LIGO/Virgo G298048: VLA observation at 15 GHz
  98. LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory
  99. LIGO/Virgo G298048: Continued monitoring of the optical counterpart candidate
  100. LIGO/Virgo G298048 ANTARES search (2)

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