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"

28041 results found.

  1. LIGO/Virgo S200225q: AstroSat CZTI upper limits
  2. LIGO/Virgo S200219ac: AstroSat CZTI upper limits
  3. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  4. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  5. LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
  6. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  7. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  8. GRB 200228B: LCO Optical Upper Limit
  9. GRB 200228B: Swift-BAT refined analysis
  10. GRB 200228B: RATIR Optical Observations
  11. GRB 200228B: Liverpool Telescope imaging
  12. GRB 200228B: Swift-XRT refined Analysis
  13. GRB 200228B: Swift/UVOT Upper Limits
  14. GRB 200228B: RATIR Optical Observations
  15. GRB 200228B: Fermi GBM observation
  16. GRB 200227A: RATIR Optical Observations
  17. IceCube-200227A: Upper limits from a search for additional neutrino events in IceCube
  18. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  19. GRB 200228C: Insight-HXMT/HE detection
  20. GRB 200228A: Fermi GBM observation
  21. GRB 200227A: Mondy optical upper limit
  22. GRB 200228B: Enhanced Swift-XRT position
  23. Fermi-LAT Gamma-ray Observations of IceCube-200227A
  24. GRB 200228B: Swift detection of a burst
  25. GRB 200227A: Insight-HXMT/HE detection
  26. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  27. GRB 200227A: Swift-XRT refined Analysis
  28. GRB 200228A: BALROG localization (Fermi Trigger 604565918 / GRB 200228291)
  29. GRB 200227A: Swift-BAT refined analysis
  30. GRB 200227A: Swift/UVOT Upper Limits
  31. GRB 200227A: Enhanced Swift-XRT position
  32. HAWC-200216A: No Neutrino Counterpart in ANTARES Search
  33. GRB 200224A: Mondy optical upper limit
  34. GRB 200227A: Fermi GBM observation
  35. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  36. IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  37. GRB 200227A: Swift detection of a burst
  38. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  39. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  40. LIGO/Virgo S200225q: Updated Sky Localization
  41. LIGO/Virgo S200219ac: Upper limits from Konus-Wind observations
  42. LIGO/Virgo S200213t: Upper limits from Konus-Wind observations
  43. LIGO/Virgo S200208q: Upper limits from Konus-Wind observations
  44. GRB 200224A: Calar Alto 2.2m optical afterglow detection
  45. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  46. LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
  47. LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
  48. LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
  49. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  50. GRB 200224B: DDOTI/OAN optical observations report
  51. LIGO/Virgo S200219ac: Updated Sky Localization
  52. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  53. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  54. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  55. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  56. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  57. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  58. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  59. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  60. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  61. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  62. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  63. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  64. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  66. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  67. GRB 200224A: Swift-BAT refined analysis
  68. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  69. GRB 200224A: LCO Upper Limits
  70. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  71. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  72. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  73. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  74. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  75. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  76. GRB 200224A: Swift/UVOT Detection
  77. GRB 200224A: Swift-XRT refined Analysis
  78. GRB 200224A: Tautenburg observations
  79. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  80. GRB 200224A: Swift detection of a burst
  81. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  82. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  83. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  84. GRB 200219C: OAJ afterglow confirmation
  85. GRB 200219A: UVOT Upper Limits
  86. GRB 200219C: Mondy and TSHAO optical observations
  87. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  88. GRB 200219C: Swift-XRT afterglow detection
  89. GRB 200219C: DDOTI Observations
  90. GRB 200219C: Fermi GBM detection
  91. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  92. GRB 200215A: LCO Optical Upper Limits
  93. GRB 200219A, Swift-BAT refined analysis
  94. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  95. Fermi trigger No 603849435: Global MASTER-Net observations report
  96. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  97. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  98. GRB 200219A: Swift-XRT refined Analysis correction
  99. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  100. GRB 200219A: Enhanced Swift-XRT position

Advanced

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