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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"

4055 results found.

  1. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume using the updated sky map computed using LALInference
  2. LIGO/Virgo G298048 : Fermi-LAT search for a high-energy gamma-ray counterpart
  3. LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival ASAS-SN Data
  4. LIGO/Virgo G298048: REM optical/NIR observations of candidate in NGC 4993
  5. LIGO/Virgo G298048: DLT40 optical candidate
  6. LIGO/Virgo G298048: DECam optical candidate
  7. LIGO/Virgo G298048: Potential optical counterpart discovered by Swope telescope
  8. LIGO/Virgo G298048 - Update on Fermi/GBM GRB 170817A Analysis
  9. LIGO/Virgo G298048: Updated sky map from gravitational-wave data
  10. LIGO/Virgo G298048: AGILE GRID observations
  11. LIGO/Virgo G298048: AGILE MCAL observations
  12. LIGO/Virgo G298048: Swift/BAT data search
  13. LIGO/Virgo G297595: Pierre Auger Observatory neutrino follow-up
  14. LIGO/Virgo G298048 ANTARES search
  15. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume with Face-on Assumption
  16. LIGO/Virgo G298048: Nearby Galaxies in the Localization Volume
  17. LIGO/Virgo G298048: Insight-HXMT observations
  18. LIGO/Virgo G298048: Potential host galaxies from the GLADE catalog
  19. LIGO/Virgo G298048: IPN triangulation of Fermi/GBM trigger 524666471/170817529
  20. LIGO/Virgo G298048: Astrosat CZTI upper limits
  21. LIGO/Virgo G298048: Further analysis of a binary neutron star candidate with updated sky localization
  22. LIGO/Virgo G297595: Liverpool Telescope observations of MASTER transients
  23. LIGO/Virgo G298048: COINCIDENT IceCube neutrino candidate with Fermi GBM trigger 524666471/170817529
  24. LIGO/Virgo G298048: correction to the luminosity distance reported in GCN 21509
  25. LIGO/Virgo G298048: Identification of a binary neutron star candidate coincident with Fermi GBM trigger 524666471/170817529
  26. LIGO/Virgo G298048: FOUND COINCIDENT IceCube neutrino observation
  27. LIGO/Virgo G298048: INTEGRAL detection of a prompt gamma-ray counterpart
  28. LIGO/Virgo G298048: Fermi GBM trigger 170817.529 and LIGO single IFO trigger
  29. LIGO/Virgo G298048: Fermi GBM trigger 524666471/170817529: LIGO/Virgo Identification of a possible gravitational-wave counterpart
  30. LIGO/Virgo G297595: Swift-XRT sources
  31. LIGO/Virgo G296853 TZAC TAROT observations
  32. LIGO/Virgo G297595: Konus-Wind observations
  33. LIGO/Virgo G297595: MASTER MASTER Bright PSN detection in error-box
  34. LIGO/Virgo G297595: INAF VST-ESO PARANAL observations
  35. LIGO/Virgo G297595: Subaru Hyper Suprime-Cam follow-up observations
  36. LIGO/Virgo G296853: Pierre Auger Observatory neutrino follow-up
  37. LIGO/Virgo G297595: REM optical/NIR observations
  38. LIGO/Virgo G297595 : MAXI/GSC observations
  39. LIGO/Virgo G297595: Updated localization from LIGO and Virgo data
  40. LIGO/Virgo G297595: Correction to luminosity distance stated in GCN 21474
  41. LIGO/Virgo G297595: Pan-STARRS coverage and transients over the first 5hrs
  42. LIGO/Virgo G297595: Insight-HXMT observations
  43. LIGO/Virgo G297595: Nearby Galaxies in the Localization Volume
  44. LIGO/Virgo G297595: Fermi GBM Observations
  45. LIGO/Virgo G297595: Swift/BAT data search
  46. LIGO/Virgo G297595: AGILE GRID observations
  47. LIGO/Virgo G297595 : Fermi-LAT search for high-energy gamma-ray counterpart
  48. LIGO/Virgo G297595 ANTARES search
  49. LIGO/Virgo G297595: INTEGRAL search for a prompt gamma-ray counterpart
  50. LIGO/Virgo G297595: AGILE MCAL observations
  51. LIGO/Virgo G297595: SPI-ACS/INTEGRAL data investigations
  52. LIGO/Virgo G297595: IceCube neutrino observations
  53. LIGO/Virgo G297595: Identification of a GW Binary Merger Candidate
  54. LIGO/Virgo G296853: Liverpool Telescope classification of MASTER OT J013646.48-140323.5
  55. LIGO/Virgo G296853: BOOTES-1 and GTC optical observations
  56. LIGO/Virgo G296853: Insight-HXMT observations
  57. LIGO/Virgo G296853 : MAXI/GSC observations
  58. LIGO/Virgo G296853: HAWC follow-up
  59. LIGO/Virgo G296853: Super-AGILE observations
  60. LIGO/Virgo G296853: MASTER SN detection near center error-area
  61. LIGO/Virgo G296853: no INTEGRAL data at the time of the event
  62. LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart
  63. LIGO/Virgo G296853: Fermi GBM Observations
  64. LIGO/Virgo G296853: AGILE GRID observations
  65. LIGO/Virgo G296853: Swift/BAT data search
  66. LIGO/Virgo G296853: MASTER follow up observations
  67. LIGO/Virgo G296853: AGILE MCAL observations
  68. LIGO/Virgo G296853 ANTARES search
  69. LIGO/Virgo G296853: IceCube neutrino observations
  70. LIGO/Virgo G296853: Identification of a GW Binary Merger Candidate
  71. LIGO/Virgo G275697: LOFAR follow-up
  72. LIGO/Virgo G288732: Konus-Wind observations
  73. LIGO/Virgo G274296: Updated localization from LIGO data
  74. LIGO/Virgo G270580: Candidate retracted due to H1 data quality
  75. LIGO/Virgo G288732: Fermi GBM Upper Limits for the LIGO Trigger and LAT Candidate
  76. LIGO/Virgo G288732: Pan-STARRS coverage of the Fermi/LAT candidate position
  77. LIGO/Virgo G288732: VLA imaging of the possible Fermi/LAT counterpart
  78. LIGO/Virgo G288732: Kiso/KWFC optical imaging of the possible Fermi/LAT counterpart
  79. LIGO/Virgo G288732: HAWC follow-up
  80. LIGO/Virgo G288732: UKIRT near-IR imaging of the Fermi/LAT candidate
  81. LIGO/Virgo G288732: LBT optical imaging of the Fermi/LAT candidate
  82. LIGO/Virgo G288732 : MAXI/GSC observations
  83. LIGO/Virgo G288732: Updated sky map from gravitational-wave data
  84. LIGO/Virgo G288732: GWFUNC/NOWT observations of the skymap and follow-up of the Fermi/LAT candidate
  85. LIGO/Virgo G288732: Swift/UVOT follow up of the possible LAT counterpart
  86. LIGO/Virgo G288732: Swift/BAT data search
  87. LIGO/Virgo G288732: Swift-XRT follow up of the putative LAT counterpart
  88. LIGO/Virgo G288732: INTEGRAL search for a prompt gamma-ray counterpart
  89. LIGO/Virgo G288732:SVOM/Mini-GWAC observations of the initial skymap
  90. LIGO/Virgo G288732: AGILE GRID Observations
  91. LIGO/Virgo G288732: Fermi-LAT detection of a weak candidate
  92. LIGO/Virgo G288732: IceCube neutrino observations update
  93. LIGO/Virgo G288732: AGILE MCAL Observations
  94. LIGO/Virgo G288732 ANTARES search
  95. LIGO/VIRGO G288732: Fermi GBM Observations
  96. LIGO/Virgo G288732: Identification of a GW Binary Merger Candidate
  97. IPN Triangulation of GRB 170529A (long)
  98. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  99. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  100. LIGO/Virgo G268556/GW170104: Konus-Wind observations

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