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"

28045 results found.

  1. GRB 191004B: GROND Detection of the Optical/NIR Afterglow
  2. GRB 191004A: GROND Upper limits
  3. GRB 191004B: COATLI Optical Observations
  4. GRB 191004A: Swift-XRT refined Analysis
  5. GRB 191004B: Swift-BAT refined analysis
  6. GRB 191004B: NOT optical photometry
  7. GRB 191004A: Swift-BAT refined analysis
  8. GRB 191004A: NOT optical upper limits
  9. GRB 191004B: Enhanced Swift-XRT position
  10. GRB 191004A: Enhanced Swift-XRT position
  11. GRB 191004B: Optical Afterglow Detection with LCO
  12. Swift GRB191004.9: Global MASTER-Net OT detection
  13. GRB 191004B: Swift detection of a burst with an optical counterpart
  14. GRB 191004A: Swift detection of a burst with an optical detection
  15. Swift GRB191004.75: Global MASTER-Net OT detection
  16. GRB 191001A: Swift-XRT observations
  17. GRB 191001B: Optical Upper Limits with LCO
  18. LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
  19. GRB 191001A: Fermi GBM observation
  20. GRB 190926A: Upper limit from CAHA 2.2m observation
  21. IceCube-191001A: HAWC follow-up
  22. LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
  23. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
  24. Fermi-LAT Gamma-ray Observations of IceCube-191001A
  25. GRB 191001B: Swift-BAT refined analysis
  26. IPN triangulation of GRB 191001A
  27. LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
  28. LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
  29. GRB 191001A: RATIR Optical and NIR Observations
  30. LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
  31. IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  32. GRB 191001A: DDOTI Optical Counterpart Candidate
  33. LIGO/Virgo S190924h: Correction to GCN 25905, updated sky localization for S190924h
  34. LIGO/Virgo S190828h: Updated Sky Localization
  35. LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
  36. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  37. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  38. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  39. GRB 191001A: BALROG localization (Fermi Trigger 591604915 / GRB 191001279)
  40. GRB 191001A: Fermi GBM Final Real-time Localization
  41. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  42. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  43. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  44. LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
  45. LIGO/Virgo S190930s: Upper limits from Fermi-GBM Observations
  46. LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
  47. LIGO/Virgo S190930s: no counterpart candidates in AGILE-GRID observations
  48. LIGO/Virgo S190928c: Retraction of GW unmodeled transient candidate
  49. LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
  50. LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
  51. LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  52. GRB 190928A: Insight-HXMT/HE detection
  53. LIGO/Virgo S190930s: No counterpart candidates in AGILE-MCAL observations
  54. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
  57. LIGO/Virgo S190930s: Upper limits from IceCube neutrino searches
  58. LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  59. LIGO/Virgo S190930s: Identification of a GW compact binary merger candidate
  60. GRB 190928A: MASTER optical observations
  61. GRB 190926A: AbAO upper optical limit
  62. LIGO/Virgo S190828j: Updated Sky Localization
  63. GRB 190926A: Swift-BAT refined analysis
  64. GRB 190926A: Upper Limit from OSN T150 Observation
  65. GRB 190926A: Swift/UVOT Upper Limits
  66. GRB 190926A: Swift-XRT refined Analysis
  67. GRB 190926A: Enhanced Swift-XRT position
  68. GRB 190926A: Swift detection of a burst
  69. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  70. LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
  71. LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
  72. LIGO/Virgo S190924h: Not observable by CALET
  73. LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
  74. LIGO/Virgo S190923y: No neutrino candidates at Pierre Auger Observatory
  75. LIGO/Virgo S190924h: Upper limits from Fermi-GBM Observations
  76. LIGO/Virgo S190924h: no counterpart candidates in AGILE-GRID observations
  77. LIGO/Virgo S190924h: No counterpart candidates in AGILE-MCAL observations
  78. Fermi-LAT Gamma-ray Observations of IceCube-190922B
  79. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  80. LIGO/Virgo S190924h : no neutrino counterpart candidate in ANTARES search
  81. LIGO/Virgo S190924h: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
  83. IceCube-190922B: Upper limits from a search for additional neutrino events in IceCube
  84. LIGO/Virgo S190924h: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo S190924h: Upper limits from IceCube neutrino searches
  86. Fermi-LAT Gamma-ray Observations of IceCube-190922A
  87. IceCube-190922B - HAWC follow-up
  88. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
  89. LIGO/Virgo S190923y: Upper limits from Fermi-GBM Observations
  90. LIGO/Virgo S190814bv: Chandra X-ray non-detection of ASKAP J005547-270433 / AT2019osy
  91. LIGO/Virgo S190923y: Upper limits from AGILE-GRID observations
  92. GRB 190923A: BALROG localization (Fermi Trigger 590942887 / GRB 190923617)
  93. LIGO/Virgo S190923y: No counterpart candidates in AGILE-MCAL observations
  94. LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations
  95. LIGO/Virgo S190923y : no neutrino counterpart candidate in ANTARES search
  96. LIGO/Virgo S190923y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  97. LIGO/Virgo S190923y: Identification of a GW compact binary merger candidate
  98. LIGO/Virgo S190923y: No counterpart candidates in HAWC observations
  99. LIGO/Virgo S190923y: Upper limits from IceCube neutrino searches
  100. IceCube-190922A: Upper limits from Fermi-GBM Observations

Advanced

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