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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"

2708 results found.

  1. GRB 160509A Gemini North redshift
  2. IceCube-160427A: iPTF Observations
  3. GRB 160417A, the review of the sky area in plate archive
  4. ICECUBE-160427A neutrino candidate event: updated direction information
  5. GRB 160425A MASTER notices: possible host galaxy in the optical error-box
  6. GRB 160409A found in Swift BAT ground analysis
  7. GRB 160408A: TLS Tautenburg observations
  8. GRB 160408A: Swift/UVOT Upper Limits
  9. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  10. GRB 160321A: Possible RATIR Optical and NIR Detections
  11. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  12. GRB 160310A: Swift/UVOT Upper Limits
  13. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  14. GRB 160307A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  15. GRB 160310A: NOT optical observations
  16. GRB 160303A: GTC imaging of possible host galaxy
  17. GRB 160303A: Observations from T150 OSN
  18. GRB 160303A: McDonald 2.1m CQUEAN Detection
  19. GRB160228A: Further analyses on spectral lag and extended emission
  20. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  21. GRB 160223B: Khureltogot optical observations
  22. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  23. GRB 160131A: second epoch observations with the GMRT
  24. Low frequency GMRT observations of GRB 160131A
  25. GRB 160131A: RATIR Optical Observations
  26. LIGO/Virgo G211117: MASTER OTs 26.XII.2015 - 01.I.2016
  27. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  28. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  29. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  30. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  31. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  32. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  33. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  34. GRB 151122A: Swift detection of a burst
  35. Swift Trigger 664610: is unlikely a GRB
  36. 610 MHz detection of GRB 151027A with the GMRT
  37. GMRT radio detection of GRB 151027A
  38. GRB 151111A: GROND marginal detection of a afterglow candidate
  39. GRB 151111A: LCOGT-FTS afterglow observations
  40. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  41. GRB 151107A: Further investigation of the source nature
  42. GRB 151107A: Swift detection of a possible burst
  43. GRB 151027A: GMG observation
  44. GRB 151027A: P60 afterglow confirmation and rebrightening
  45. LIGO/Virgo G194575: CQUEAN/LOAO observations
  46. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  47. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  48. LIGO Virgo G194575: TZAC TAROT observations
  49. Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
  50. Swift Trigger 657564: XRT prompt analysis
  51. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  52. LIGO/Virgo G184098: spectral classification of PS15cci
  53. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  54. GRB 150906B: Further analysis of the Konus-Wind data
  55. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  56. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  57. ANTARES neutrino detection and possible Swift X-ray counterpart
  58. GRB 150818A: possible SN rise in light curve of Mondy observations
  59. Swift Trigger 652046 is probably not a GRB
  60. GRB 150728A: FTN observations
  61. GRB 150720A: Swift-XRT refined Analysis
  62. Swift Trigger 649706: a possible GRB or bright Galactic transient
  63. Swift-XRT observations of GRB 150710A
  64. GRB 150710A: RATIR Observations
  65. Swift Trigger 648422: Swift-XRT observations
  66. Trigger 648422: Swift possible detection of a source in NGC4552
  67. Swift Trigger 645340: a possible GRB
  68. V404 Cyg: Fermi GBM observations
  69. GRB 150518A: possible SN observations
  70. Swift trigger 642453 is not an astrophysical source
  71. Swift Trigger 642453: a possible GRB
  72. GRB 150518A: MAXI-GSC further analysis
  73. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  74. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  75. GRB 150518A: SAO RAS optical observations
  76. Swift Trigger 639636: a possible GRB
  77. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  78. GRB150418A: Swift/UVOT did not detect a new source
  79. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  80. GRB 150407A: optical observations
  81. GRB 150407A: Swift detection of a possible burst
  82. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  83. GRB 150323C: additional optical observations in Mondy
  84. GRB 141121A: GMG observation
  85. GRB 150323C: possible host galaxy detection
  86. Swift Trigger 635306 is probably not an astrophysical source
  87. GRB 150220A, the review of the sky area in plate archives
  88. GRB 150314A: Fermi-LAT detection
  89. GRB 150311A: MAXI/GSC possible afterglow detection
  90. GRB 150309A: Swift-BAT refined analysis
  91. GRB 150301C: VLA Observations
  92. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  93. GRB 150301C : (Swift trigger 633105) Swift observations
  94. Swift Trigger 633173 is probably not an astrophysical source
  95. Trigger 633105 is likely not a GRB
  96. GRB 150213B, the review of the sky area in plate archives
  97. GRB 150212A, the review of the sky area in plate archives
  98. GRB 150206B: Fermi GBM detection
  99. GRB 150204A: Swift/UVOT Upper Limits
  100. GRB 150201A: Fermi GBM observation

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