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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"

3109 results found.

  1. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  2. GRB 170210A: POLAR observation
  3. IPN Triangulation of GRB 170210A
  4. GRB 170210A: Fermi GBM observation
  5. Konus-Wind observation of GRB 170209A
  6. GRB 170208A: Swift-BAT refined analysis
  7. GRB 170202A: SQUEAN Observation
  8. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  9. GRB 170115B: AGILE/SuperAGILE localisation
  10. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  11. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  12. GRB 170121B: MASTER early optical observations of the Swift possible XT
  13. LIGO/Virgo G268556/GW170104: MAXI/GSC observations
  14. GRB 170121B/Fermi trigger 506702667 MASTER-Amur OT detection
  15. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  16. GRB 170112A : AbAO optical observations
  17. GRB 170113A: Fermi GBM observations
  18. GRB 170112A: MASTER-OAFA (Argentina) early optical observations
  19. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  20. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  21. LIGO/Virgo G268556: Continued iPTF Observations and Additional Optical Transient Candidates
  22. LIGO/Virgo G268556: SWASP optical imaging
  23. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  24. LIGO/Virgo G268556: Swift-XRT sources
  25. GRB 170101B: POLAR observation
  26. GRB 170101B: Lomonosov BDRG gamma ray discovery
  27. GRB 170101B: Astrosat CZTI detection
  28. GRB 170101B: Fermi GBM detection
  29. GRB 161214A: MASTER-IAC early optical observations
  30. GRB161219.78 MASTER-Net OT detection
  31. GRB 161219B: Rapid ALMA Observations & Detection
  32. GRB 161220A: Swift-XRT refined Analysis
  33. GRB 161219B: VLA Detection
  34. GRB 161219B: Swift/UVOT Detection
  35. GRB 161219B: LCO Sutherland observations
  36. GRB 161219B: Enhanced Swift-XRT position
  37. GRB 161219B: Swift detection of a burst with an optical afterglow
  38. GRB 161218A: CALET Gamma-Ray Burst Monitor detection
  39. Konus-Wind observation of GRB 161218A
  40. GRB 161218A: POLAR observation
  41. GRB 161218A: Swift detection of a burst
  42. GRB 161129A: ISON/UAFO optical observations
  43. GRB 161117A: SMARTS optical/IR afterglow observations
  44. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  45. Konus-Wind observation of GRB 161117A
  46. GRB 161108A: NOT redshift
  47. IceCube-161103: MASTER follow-up observations
  48. GRB 161023A: LCOGT-FTS optical observations
  49. GRB 161023A (Integral trigger 7613) MASTER-Net bright OT detection
  50. Swift Trigger 718766 is not an astrophysical event.
  51. GRB 161017A: Lomonosov Gamma Ray and MASTER Optical prompt observations
  52. GRB 161014A: AROMA-N Optical Observation
  53. GRB 161014A : Xinglong TNT optical observation
  54. GRB 161010A: Swift/UVOT Possible Detection
  55. GRB 161010A: Swift-XRT afterglow detection
  56. GRB 160927A: 15 GHz upper limits from AMI
  57. GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
  58. GRB 161001A: GROND afterglow candidate
  59. GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
  60. GRB 161001A: Prompt enhanced Swift-XRT position
  61. GRB 160917A: Fermi GBM observation
  62. GRB 160910A: Swift-XRT afterglow detection
  63. GRB 160910A: Fermi GBM observation
  64. GRB 160905A: Swift detection of a burst with an optical counterpart
  65. Konus-Wind observation of GRB 160821A
  66. GRB 160816A: TSHAO optical observations
  67. BAT detection and localization of GRB 160819A
  68. GRB 160816A: ISON/UAFO optical observations
  69. IceCube 160806A: Lomonosov BDRG gamma ray prompt observations
  70. IPN Triangulation of GRB 160806A
  71. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  72. Swift Trigger 707517 is probably not a GRB
  73. IPN Triangulation of GRB 160802A
  74. GRB 160804A: Swift detection of a burst
  75. GRB 160714A: MASTER early optical observations
  76. GRB 160714A: Swift-XRT observations
  77. GRB 160712A: Swift-XRT observations
  78. GRB 160625B: Global MASTER-Crimea prompt optical emission detection (fwd)
  79. GRB 160705A/MAXI J0748-149: MAXI/GSC detection
  80. GRB 160629A: AbAO optical observations
  81. GRB 160525B: Mondy optical upper limit
  82. Swift detection of SGR 1935+2154
  83. GRB 160521B: Fermi-LAT detection
  84. GRB 160521B: Fermi GBM detection
  85. GRB 160509A: VLA Detection
  86. GRB 160509A Gemini North candidate afterglow
  87. GRB 160509A: Swift-XRT afterglow detection
  88. GRB 160506A: IRSF upper limits
  89. VERITAS rapid follow-up observations of IceCube event 160427A
  90. GRB 160501A: Swift/UVOT Upper Limits
  91. MASTER search for counterpart to the IceCube event 67093193 (run 127853)
  92. LIGO Virgo G211117: Additional MWA Observations
  93. GRB 160409A found in Swift BAT ground analysis
  94. IPN Triangulation of GRB 160406A (short/hard)
  95. LIGO/Virgo G211117: LOFAR follow-up
  96. GRB 160303A SMA observation
  97. GRB 160227A: McDonald 0.8m Detection
  98. GRB 160227A: MAXI/GSC detection
  99. GRB 160225A: TSHAO optical upper limit
  100. Konus-Wind observation of GRB 160220B

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