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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"

3116 results found.

  1. GRB 170220A: POLAR Observation
  2. LIGO/Virgo G274296: J-GEM optical/NIR follow-up observations
  3. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  4. LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
  5. Konus-Wind observation of GRB 170219A (short/hard)
  6. LIGO/Virgo G274296: Pan-STARRS imaging and discovery of 70 transients
  7. GRB 170210A: POLAR observation
  8. IPN Triangulation of GRB 170210A
  9. GRB 170210A: Fermi GBM observation
  10. Konus-Wind observation of GRB 170209A
  11. GRB 170208A: Swift-BAT refined analysis
  12. GRB 170202A: SQUEAN Observation
  13. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  14. GRB 170115B: AGILE/SuperAGILE localisation
  15. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  16. LIGO/Virgo G270580: Pan-STARRS coverage and 124 optical transients
  17. GRB 170121B: MASTER early optical observations of the Swift possible XT
  18. LIGO/Virgo G268556/GW170104: MAXI/GSC observations
  19. GRB 170121B/Fermi trigger 506702667 MASTER-Amur OT detection
  20. LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
  21. GRB 170112A : AbAO optical observations
  22. GRB 170113A: Fermi GBM observations
  23. GRB 170112A: MASTER-OAFA (Argentina) early optical observations
  24. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  25. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  26. LIGO/Virgo G268556: Continued iPTF Observations and Additional Optical Transient Candidates
  27. LIGO/Virgo G268556: SWASP optical imaging
  28. LIGO/Virgo G211117 / GW151226: LOFAR follow-up
  29. LIGO/Virgo G268556: Swift-XRT sources
  30. GRB 170101B: POLAR observation
  31. GRB 170101B: Lomonosov BDRG gamma ray discovery
  32. GRB 170101B: Astrosat CZTI detection
  33. GRB 170101B: Fermi GBM detection
  34. GRB 161214A: MASTER-IAC early optical observations
  35. GRB161219.78 MASTER-Net OT detection
  36. GRB 161219B: Rapid ALMA Observations & Detection
  37. GRB 161220A: Swift-XRT refined Analysis
  38. GRB 161219B: VLA Detection
  39. GRB 161219B: Swift/UVOT Detection
  40. GRB 161219B: LCO Sutherland observations
  41. GRB 161219B: Enhanced Swift-XRT position
  42. GRB 161219B: Swift detection of a burst with an optical afterglow
  43. GRB 161218A: CALET Gamma-Ray Burst Monitor detection
  44. Konus-Wind observation of GRB 161218A
  45. GRB 161218A: POLAR observation
  46. GRB 161218A: Swift detection of a burst
  47. GRB 161129A: ISON/UAFO optical observations
  48. GRB 161117A: SMARTS optical/IR afterglow observations
  49. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  50. Konus-Wind observation of GRB 161117A
  51. GRB 161108A: NOT redshift
  52. IceCube-161103: MASTER follow-up observations
  53. GRB 161023A: LCOGT-FTS optical observations
  54. GRB 161023A (Integral trigger 7613) MASTER-Net bright OT detection
  55. Swift Trigger 718766 is not an astrophysical event.
  56. GRB 161017A: Lomonosov Gamma Ray and MASTER Optical prompt observations
  57. GRB 161014A: AROMA-N Optical Observation
  58. GRB 161014A: Swift/UVOT Detection
  59. GRB 161014A : Xinglong TNT optical observation
  60. GRB 161010A: Swift/UVOT Possible Detection
  61. GRB 161010A: Swift-XRT afterglow detection
  62. GRB 160927A: 15 GHz upper limits from AMI
  63. GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
  64. GRB 161001A: GROND afterglow candidate
  65. GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
  66. GRB 161001A: Prompt enhanced Swift-XRT position
  67. GRB 160917A: Fermi GBM observation
  68. GRB 160910A: Swift-XRT afterglow detection
  69. GRB 160910A: Fermi GBM observation
  70. GRB 160905A: Swift detection of a burst with an optical counterpart
  71. Konus-Wind observation of GRB 160821A
  72. GRB 160816A: TSHAO optical observations
  73. BAT detection and localization of GRB 160819A
  74. GRB 160816A: ISON/UAFO optical observations
  75. IceCube 160806A: Lomonosov BDRG gamma ray prompt observations
  76. IPN Triangulation of GRB 160806A
  77. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  78. Swift Trigger 707517 is probably not a GRB
  79. IPN Triangulation of GRB 160802A
  80. GRB 160804A: Swift detection of a burst
  81. GRB 160714A: MASTER early optical observations
  82. GRB 160714A: Swift-XRT observations
  83. GRB 160712A: Swift-XRT observations
  84. GRB 160625B: Global MASTER-Crimea prompt optical emission detection (fwd)
  85. GRB 160705A/MAXI J0748-149: MAXI/GSC detection
  86. GRB 160629A: AbAO optical observations
  87. GRB 160525B: Mondy optical upper limit
  88. Swift detection of SGR 1935+2154
  89. GRB 160521B: Fermi-LAT detection
  90. GRB 160521B: Fermi GBM detection
  91. GRB 160509A: VLA Detection
  92. GRB 160509A Gemini North candidate afterglow
  93. GRB 160509A: Swift-XRT afterglow detection
  94. GRB 160506A: IRSF upper limits
  95. VERITAS rapid follow-up observations of IceCube event 160427A
  96. MASTER search for counterpart to the IceCube event 67093193 (run 127853)
  97. LIGO Virgo G211117: Additional MWA Observations
  98. GRB 160409A found in Swift BAT ground analysis
  99. IPN Triangulation of GRB 160406A (short/hard)
  100. LIGO/Virgo G211117: LOFAR follow-up

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