Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

19549 results found.

  1. GRB 191029A: Swift-XRT observations
  2. IPN triangulation of GRB 191027A
  3. Swift Trigger 931484 is not a GRB
  4. Swift Trigger 931384: possible GRB 191025A
  5. GRB 191024A: Swift-BAT refined analysis
  6. GRB 191024A: Swift/UVOT Upper Limits
  7. GRB 191024A: VLT/X-shooter optical observations
  8. GRB 191024A: GROND early upper limits
  9. GRB 191024A: Enhanced Swift-XRT position
  10. GRB 191024A: Swift detection of a burst
  11. GRB 191019A: Nanshan-0.6m optical observations
  12. GRB 191019A: Swift/UVOT Detection
  13. HAWC-191019A: No Neutrino Counterpart detected with ANTARES
  14. GRB 191019A: Enhanced Swift-XRT position
  15. GRB 191019A: GROND observations
  16. GRB 191019A: NOT optical observations
  17. Alert from the HAWC Burst Monitor HAWC-191019A
  18. GRB 191019A: TSHAO optical observations, probable afterglow and host galaxy
  19. GRB 191019A: Swift-XRT observations
  20. GRB 191017B: Swift-BAT refined analysis
  21. GRB 191017B: Swift/UVOT Upper Limits
  22. GRB 191016A: REM optical observations
  23. GRB 191016A: Swift-XRT afterglow detection
  24. GRB 191016A: Swift/UVOT Detection
  25. GRB 191017B: Enhanced Swift-XRT position
  26. GRB 191017B: Swift detection of a burst
  27. GRB 191016A: AZT-20 (Assy observatory) optical photometry
  28. GRB 191016A: early time BOOTES Network and follow-up 1.5m OSN optical observations
  29. GRB 191016A: RATIR Optical and NIR Observations
  30. GRB 191016A: COATLI Optical Observations and Detection of the Afterglow
  31. GRB 191016A: Swift detection of a burst
  32. GRB 191011A: Swift-BAT refined analysis
  33. GRB 191011A: Swift/UVOT Detection
  34. GRB 191011A: RATIR Optical and NIR Observations
  35. GRB 191011A: Enhanced Swift-XRT position
  36. GRB 191011A: correction of reported magnitudes
  37. GRB 191011A: GROND Detection of the Optical/NIR afterglow
  38. GRB 191011A: VLT X-shooter redshift from RRM Observations
  39. GRB 191011A: Swift detection of a burst with an optical counterpart
  40. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  41. TESS Detection of the Optical Emission from the Possible Untriggered GRB Associated with ZTF19abvizsw
  42. GRB 191008A: Fermi GBM Final Real-time Localization
  43. GRB 191004B: Swift/UVOT Detection
  44. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  45. GRB 191004A: Swift/UVOT Detection
  46. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  47. LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
  48. LIGO/Virgo S190930t: Swift J221951-484240 optical photometry of Chilescope observatory
  49. LIGO/Virgo S190930t: SALT optical spectroscopy of Swift J221951-484240
  50. GRB 191004B: GROND Detection of the Optical/NIR Afterglow
  51. GRB 191004A: GROND Upper limits
  52. GRB 191004B: COATLI Optical Observations
  53. GRB 191004B: VLT/X-shooter redshift
  54. GRB 191004B: NOT optical photometry
  55. GRB 191004A: NOT optical upper limits
  56. GRB 191004B: Enhanced Swift-XRT position
  57. GRB 191004A: Enhanced Swift-XRT position
  58. GRB 191004B: Swift detection of a burst with an optical counterpart
  59. GRB 191004A: Swift detection of a burst with an optical detection
  60. GRB 191001A: Swift-XRT observations
  61. GRB 191001B: Optical Upper Limits with LCO
  62. LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
  63. GRB 190926A: Upper limit from CAHA 2.2m observation
  64. IceCube-191001A: HAWC follow-up
  65. Fermi-LAT Gamma-ray Observations of IceCube-191001A
  66. IPN triangulation of GRB 191001A
  67. LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
  68. GRB 191001A: Swift ToO observations
  69. LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
  70. GRB 191001A: RATIR Optical and NIR Observations
  71. LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
  72. IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  73. GRB 191001A: DDOTI Optical Counterpart Candidate
  74. LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
  75. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  76. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  77. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  78. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  79. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  80. LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
  81. LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
  82. LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
  83. LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  84. LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  85. GRB 190926A: AbAO upper optical limit
  86. GRB 190926A: Upper Limit from OSN T150 Observation
  87. GRB 190926A: Swift/UVOT Upper Limits
  88. GRB 190926A: Enhanced Swift-XRT position
  89. GRB 190926A: Swift detection of a burst
  90. LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
  91. LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
  92. LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
  93. LIGO/Virgo S190923y: No neutrino candidates at Pierre Auger Observatory
  94. Fermi-LAT Gamma-ray Observations of IceCube-190922B
  95. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  96. LIGO/Virgo S190924h : no neutrino counterpart candidate in ANTARES search
  97. LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
  98. Fermi-LAT Gamma-ray Observations of IceCube-190922A
  99. IceCube-190922B - HAWC follow-up
  100. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov