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"

28048 results found.

  1. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  2. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
  3. LIGO/Virgo S200105ae: AstroSat CZTI upper limits
  4. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo S200105ae: No counterpart candidates in HAWC observations
  6. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  7. LIGO/Virgo S200105ae: Upper limits from IceCube neutrino searches
  8. LIGO/Virgo S200105ae: Upper limits from Fermi-GBM Observations
  9. LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  10. LIGO/Virgo S200105ae : no neutrino counterpart candidate in ANTARES search
  11. LIGO/Virgo S200105ae: A subthreshold GW compact binary merger candidate
  12. GRB 200105A: MAXI/GSC detection
  13. Fermi-LAT Gamma-ray Observations of IceCube-191231A
  14. IceCube-191231A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 191228A: Early Optical Upper Limits from LCO
  16. IceCube-191231A: No significant detection in HAWC
  17. GRB 200101A: Fermi GBM detection
  18. GRB 200101A: BALROG localization (Fermi Trigger 599603971 / GRB 200101861)
  19. GRB 200101A: Fermi GBM Final Real-time Localization
  20. IceCube-191231A: No Neutrino Counterpart in ANTARES data
  21. IceCube-191231A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  22. GRB 191227A: Insight-HXMT/HE observation
  23. GRB 191227B: Insight-HXMT/HE observation
  24. GRB 191228A: Mondy optical upper limit
  25. IPN triangulation of GRB 191227B (short)
  26. GRB 191228A: Swift/UVOT Upper Limits
  27. GRB 191228A: Swift-XRT refined Analysis
  28. GRB 191227A: Swift-BAT refined analysis
  29. GRB 191228A: Swift-BAT refined analysis
  30. GRB 191228A: Enhanced Swift-XRT position
  31. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  32. GRB 191228A: UKIRT NIR upper limit
  33. LIGO/Virgo S191222n: No transient candidates in CALET observations
  34. GRB 191228A: Swift detection of a burst
  35. GRB 191227A: Fermi GBM detection
  36. GRB 191227A: Marginal detection by Fermi-LAT
  37. GRB 191227A: MITSuME Akeno optical upper limits
  38. Swift GRB191227A: Global MASTER-Net OT detection
  39. Swift Triggers 946256 and 946257 are not a GRB
  40. Swift Trigger 946234 is probably not a GRB
  41. GRB 191225B: BALROG localization (Fermi Trigger 598988276 / GRB 191225735)
  42. LIGO/Virgo S191205ah: MASTER OT detection
  43. LIGO/Virgo S191213g: Pan-STARRS monitoring shows PS19hgw (AT2019wxt) to be fading quickly
  44. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  45. GRB 191221B: Swift/UVOT Detection
  46. GRB 191221B: Insight-HXMT/HE detection
  47. LIGO/Virgo S191222n: Updated Sky Localization
  48. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  49. LIGO/Virgo S191216ap: Updated Source Classification
  50. LIGO/Virgo S191216ap: Upper limits from Insight-HXMT/HE observations
  51. GRB 191221B: iTelescope T17 detection
  52. LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
  53. GRB 191221B: Swift-BAT refined analysis
  54. GRB 191221B: Zadko observatory - Gingin optical observations
  55. GRB 191221B: LCO Optical Detection
  56. GRB 191221B: Swift-XRT refined Analysis
  57. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  58. LIGO/Virgo S191222n: no counterpart candidates in the Swift/BAT observations
  59. LIGO/Virgo S191222n: No counterpart candidates in Fermi-LAT observations
  60. GRB 191221B: MASTER VWFC OT yearly detection
  61. GRB 191221B: Correction to GCN26551 - VIRT OT observation
  62. GRB 191221B: VIRT Optical Upper Limits
  63. LIGO/Virgo S191222n : no neutrino counterpart candidate in ANTARES search
  64. LIGO/Virgo S191222n: upper limits from AGILE-GRID observations
  65. LIGO/Virgo S191222n: upper limits from AGILE/MCAL observations
  66. LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
  67. LIGO/Virgo S191222n: No counterpart candidates in HAWC observations
  68. LIGO/Virgo S191222n: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo S191222n: Upper limits from IceCube neutrino searches
  70. GRB 191221B: Enhanced Swift-XRT position
  71. GRB 191220A: Swift-BAT refined analysis
  72. GRB 191221B: Swift detection of a burst and a very bright optical candidate
  73. LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
  74. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  75. LIGO/Virgo S191213g: VLA follow-up of AT2019wxt/PS19hg
  76. GRB 191220A: Swift/UVOT Upper Limits
  77. GRB 191220A: AbAO optical observations
  78. GRB 191220A: Swift-XRT refined Analysis
  79. Fermi trigger No 598543714: Global MASTER-Net observations report
  80. GRB 191220A: Enhanced Swift-XRT position
  81. LIGO/Virgo S191213g: AT2019wxt 10.4m GTC spectroscopy
  82. LIGO/Virgo S191213g : SAO 1-m optical observation of AT2019wxt (PS19hgw)
  83. GRB 191220A: SAO RAS possible OT detection
  84. LIGO/Virgo S191215w: Updated Sky Localization
  85. GRB 191220A: Swift detection of a burst
  86. LIGO/Virgo S191216ap: AstroSat CZTI upper limits
  87. LIGO/Virgo S191216ap: UPDATED list of galaxies coincident with LIGO/Virgo LALInference skymap and HAWC positions
  88. LIGO/Virgo S191216ap: Updated Sky Localization
  89. LIGO/Virgo S191213g: Swift UVOT/XRT observations of Pan-STARRS1 candidate: PS19hgw
  90. LIGO/Virgo S191213g: Palomar 60-inch imaging of AT2019wxt
  91. LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
  92. LIGO/Virgo S191216ap: No candidates found in J-GEM follow-up observations of HAWC error region
  93. GRB 191218A: Swift-BAT refined analysis
  94. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  95. LIGO/Virgo S191216ap and IceCube neutrino: no counterpart candidates from AGILE-GRID observations
  96. Konus-Wind observation of GRB 191213A (ulong)
  97. LIGO/Virgo S191216ap: GRAWITA Loiano observations of HAWC error region
  98. LIGO/Virgo S191216ap: No transient candidates in CALET observations
  99. LIGO/Virgo S191216ap: CORRECTED list of galaxies coincident with LIGO/Virgo and HAWC positions
  100. LIGO/Virgo S191216ap: Nanshan follow-up 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