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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"

2707 results found.

  1. IceCube-160427A: iPTF Observations
  2. GRB 160417A, the review of the sky area in plate archive
  3. ICECUBE-160427A neutrino candidate event: updated direction information
  4. GRB 160425A MASTER notices: possible host galaxy in the optical error-box
  5. GRB 160409A found in Swift BAT ground analysis
  6. GRB 160408A: TLS Tautenburg observations
  7. GRB 160408A: Swift/UVOT Upper Limits
  8. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  9. GRB 160321A: Possible RATIR Optical and NIR Detections
  10. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  11. GRB 160310A: Swift/UVOT Upper Limits
  12. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  13. GRB 160307A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  14. GRB 160310A: NOT optical observations
  15. GRB 160303A: GTC imaging of possible host galaxy
  16. GRB 160303A: Observations from T150 OSN
  17. GRB 160303A: McDonald 2.1m CQUEAN Detection
  18. GRB160228A: Further analyses on spectral lag and extended emission
  19. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  20. GRB 160223B: Khureltogot optical observations
  21. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  22. GRB 160131A: second epoch observations with the GMRT
  23. Low frequency GMRT observations of GRB 160131A
  24. GRB 160131A: RATIR Optical Observations
  25. LIGO/Virgo G211117: MASTER OTs 26.XII.2015 - 01.I.2016
  26. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  27. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  28. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  29. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  30. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  31. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  32. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  33. GRB 151122A: Swift detection of a burst
  34. Swift Trigger 664610: is unlikely a GRB
  35. 610 MHz detection of GRB 151027A with the GMRT
  36. GMRT radio detection of GRB 151027A
  37. GRB 151111A: GROND marginal detection of a afterglow candidate
  38. GRB 151111A: LCOGT-FTS afterglow observations
  39. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  40. GRB 151107A: Further investigation of the source nature
  41. GRB 151107A: Swift detection of a possible burst
  42. GRB 151027A: GMG observation
  43. GRB 151027A: P60 afterglow confirmation and rebrightening
  44. LIGO/Virgo G194575: CQUEAN/LOAO observations
  45. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  46. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  47. LIGO Virgo G194575: TZAC TAROT observations
  48. Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
  49. Swift Trigger 657564: XRT prompt analysis
  50. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  51. LIGO/Virgo G184098: spectral classification of PS15cci
  52. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  53. GRB 150906B: Further analysis of the Konus-Wind data
  54. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  55. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  56. ANTARES neutrino detection and possible Swift X-ray counterpart
  57. GRB 150818A: possible SN rise in light curve of Mondy observations
  58. Swift Trigger 652046 is probably not a GRB
  59. GRB 150728A: FTN observations
  60. GRB 150720A: Swift-XRT refined Analysis
  61. Swift Trigger 649706: a possible GRB or bright Galactic transient
  62. Swift-XRT observations of GRB 150710A
  63. GRB 150710A: RATIR Observations
  64. Swift Trigger 648422: Swift-XRT observations
  65. Trigger 648422: Swift possible detection of a source in NGC4552
  66. Swift Trigger 645340: a possible GRB
  67. V404 Cyg: Fermi GBM observations
  68. GRB 150518A: possible SN observations
  69. Swift trigger 642453 is not an astrophysical source
  70. Swift Trigger 642453: a possible GRB
  71. GRB 150518A: MAXI-GSC further analysis
  72. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  73. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  74. GRB 150518A: SAO RAS optical observations
  75. Swift Trigger 639636: a possible GRB
  76. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  77. GRB150418A: Swift/UVOT did not detect a new source
  78. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  79. GRB 150407A: optical observations
  80. GRB 150407A: Swift detection of a possible burst
  81. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  82. GRB 150323C: additional optical observations in Mondy
  83. GRB 141121A: GMG observation
  84. GRB 150323C: possible host galaxy detection
  85. Swift Trigger 635306 is probably not an astrophysical source
  86. GRB 150220A, the review of the sky area in plate archives
  87. GRB 150314A: Fermi-LAT detection
  88. GRB 150311A: MAXI/GSC possible afterglow detection
  89. GRB 150309A: Swift-BAT refined analysis
  90. GRB 150301C: VLA Observations
  91. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  92. GRB 150301C : (Swift trigger 633105) Swift observations
  93. Swift Trigger 633173 is probably not an astrophysical source
  94. Trigger 633105 is likely not a GRB
  95. GRB 150213B, the review of the sky area in plate archives
  96. GRB 150212A, the review of the sky area in plate archives
  97. GRB 150206B: Fermi GBM detection
  98. GRB 150204A: Swift/UVOT Upper Limits
  99. GRB 150201A: Fermi GBM observation
  100. GRB 150120A: 9.8 GHz VLA upper limit

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