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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"

2900 results found.

  1. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  2. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  3. GRB 170121B: MASTER early optical observations of the Swift possible XT
  4. LIGO/Virgo G268556/GW170104: MAXI/GSC observations
  5. GRB 170121B/Fermi trigger 506702667 MASTER-Amur OT detection
  6. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  7. GRB 170112A : AbAO optical observations
  8. GRB 170113A: Fermi GBM observations
  9. GRB 170112A: MASTER-OAFA (Argentina) early optical observations
  10. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  11. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  12. LIGO/Virgo G268556: Continued iPTF Observations and Additional Optical Transient Candidates
  13. LIGO/Virgo G268556: SWASP optical imaging
  14. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  15. LIGO/Virgo G268556: Swift-XRT sources
  16. GRB 170101B: POLAR observation
  17. GRB 170101B: Lomonosov BDRG gamma ray discovery
  18. GRB 170101B: Astrosat CZTI detection
  19. GRB 170101B: Fermi GBM detection
  20. GRB 161214A: MASTER-IAC early optical observations
  21. GRB161219.78 MASTER-Net OT detection
  22. GRB 161219B: Rapid ALMA Observations & Detection
  23. GRB 161220A: Swift-XRT refined Analysis
  24. GRB 161219B: VLA Detection
  25. GRB 161219B: Swift/UVOT Detection
  26. GRB 161219B: LCO Sutherland observations
  27. GRB 161219B: Enhanced Swift-XRT position
  28. GRB 161219B: Swift detection of a burst with an optical afterglow
  29. GRB 161218A: CALET Gamma-Ray Burst Monitor detection
  30. Konus-Wind observation of GRB 161218A
  31. GRB 161218A: POLAR observation
  32. GRB 161218A: Swift detection of a burst
  33. GRB 161129A: ISON/UAFO optical observations
  34. GRB 161117A: SMARTS optical/IR afterglow observations
  35. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  36. Konus-Wind observation of GRB 161117A
  37. GRB 161108A: NOT redshift
  38. IceCube-161103: MASTER follow-up observations
  39. GRB 161023A: LCOGT-FTS optical observations
  40. GRB 161023A (Integral trigger 7613) MASTER-Net bright OT detection
  41. Swift Trigger 718766 is not an astrophysical event.
  42. GRB 161017A: Lomonosov Gamma Ray and MASTER Optical prompt observations
  43. GRB 161014A: AROMA-N Optical Observation
  44. GRB 161014A : Xinglong TNT optical observation
  45. GRB 161010A: Swift/UVOT Possible Detection
  46. GRB 161010A: Swift-XRT afterglow detection
  47. GRB 160927A: 15 GHz upper limits from AMI
  48. GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
  49. GRB 161001A: GROND afterglow candidate
  50. GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
  51. GRB 161001A: Prompt enhanced Swift-XRT position
  52. GRB 160917A: Fermi GBM observation
  53. GRB 160910A: Swift-XRT afterglow detection
  54. GRB 160910A: Fermi GBM observation
  55. GRB 160905A: Swift detection of a burst with an optical counterpart
  56. Konus-Wind observation of GRB 160821A
  57. GRB 160816A: TSHAO optical observations
  58. BAT detection and localization of GRB 160819A
  59. GRB 160816A: ISON/UAFO optical observations
  60. IceCube 160806A: Lomonosov BDRG gamma ray prompt observations
  61. IPN Triangulation of GRB 160806A
  62. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  63. Swift Trigger 707517 is probably not a GRB
  64. IPN Triangulation of GRB 160802A
  65. GRB 160804A: Swift detection of a burst
  66. GRB 160714A: MASTER early optical observations
  67. GRB 160714A: Swift-XRT observations
  68. GRB 160712A: Swift-XRT observations
  69. GRB 160625B: Global MASTER-Crimea prompt optical emission detection (fwd)
  70. GRB 160705A/MAXI J0748-149: MAXI/GSC detection
  71. GRB 160629A: AbAO optical observations
  72. GRB 160525B: Mondy optical upper limit
  73. Swift detection of SGR 1935+2154
  74. GRB 160521B: Fermi-LAT detection
  75. GRB 160521B: Fermi GBM detection
  76. GRB 160509A: VLA Detection
  77. GRB 160509A Gemini North candidate afterglow
  78. GRB 160509A: Swift-XRT afterglow detection
  79. GRB 160506A: IRSF upper limits
  80. VERITAS rapid follow-up observations of IceCube event 160427A
  81. GRB 160501A: Swift/UVOT Upper Limits
  82. MASTER search for counterpart to the IceCube event 67093193 (run 127853)
  83. LIGO Virgo G211117: Additional MWA Observations
  84. GRB 160409A found in Swift BAT ground analysis
  85. IPN Triangulation of GRB 160406A (short/hard)
  86. LIGO/Virgo G211117: LOFAR follow-up
  87. GRB 160303A SMA observation
  88. GRB 160227A: McDonald 0.8m Detection
  89. GRB 160227A: MAXI/GSC detection
  90. GRB 160225A: TSHAO optical upper limit
  91. Konus-Wind observation of GRB 160220B
  92. GRB 160220A: MASTER-Amur observations
  93. LIGO/Virgo G211117: LOFAR follow-up
  94. GRB 160206A: MAXI/GSC detection
  95. GRB 160203A: Enhanced Swift-XRT position
  96. GRB 160203A: GROND Afterglow Candidate
  97. GRB 160203A: Swift detection of a burst
  98. GRB 160123A: Swift-BAT refined analysis
  99. IPN Triangulation of GRB 151231A
  100. LIGO/Virgo G211117: Subaru Hyper Suprime-Cam follow-up observation

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