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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"

2623 results found.

  1. GRB 160623A: Possible detection of a radio afterglow at 15 GHz with AMI
  2. GRB 160624A: Lulin observation
  3. GRB160624A:possible GRB host redshift
  4. Fermi GBM Trigger 160622573 is not a GRB
  5. BAT trigger 700791 (possible GRB 160622A) is SNR RCW 103
  6. GRB 160622A: Swift detection of a possible short GRB or a new SGR
  7. Trigger 689956: Swift detection of a source near the Galactic center
  8. Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
  9. GRB 160530A: discovery with the Compton Spectrometer and Imager
  10. GRB 160525A: Swift-BAT refined analysis
  11. GRB 160521B: Theoretical estimate of the redshift and urgent need for further x-ray observations
  12. GRB 160425A: SMARTS late-time observations
  13. GRB 160521B: Swift/UVOT Upper Limits
  14. Fermi GBM triggers of SGR 1935+2154
  15. Interplanetary Network Search for IceCube 160427A
  16. GRB 160509A Gemini North redshift
  17. IceCube-160427A: iPTF Observations
  18. GRB 160417A, the review of the sky area in plate archive
  19. ICECUBE-160427A neutrino candidate event: updated direction information
  20. GRB 160425A MASTER notices: possible host galaxy in the optical error-box
  21. GRB 160409A found in Swift BAT ground analysis
  22. GRB 160408A: TLS Tautenburg observations
  23. GRB 160408A: Swift/UVOT Upper Limits
  24. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  25. GRB 160321A: Possible RATIR Optical and NIR Detections
  26. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  27. GRB 160310A: Swift/UVOT Upper Limits
  28. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  29. GRB 160307A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  30. GRB 160310A: NOT optical observations
  31. GRB 160303A: GTC imaging of possible host galaxy
  32. GRB 160303A: Observations from T150 OSN
  33. GRB 160303A: McDonald 2.1m CQUEAN Detection
  34. GRB160228A: Further analyses on spectral lag and extended emission
  35. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  36. GRB 160223B: Khureltogot optical observations
  37. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  38. GRB 160131A: second epoch observations with the GMRT
  39. Low frequency GMRT observations of GRB 160131A
  40. GRB 160131A: RATIR Optical Observations
  41. LIGO/Virgo G211117: MASTER OTs 26.XII.2015 - 01.I.2016
  42. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  43. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  44. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  45. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  46. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  47. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  48. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  49. GRB 151122A: Swift detection of a burst
  50. Swift Trigger 664610: is unlikely a GRB
  51. 610 MHz detection of GRB 151027A with the GMRT
  52. GMRT radio detection of GRB 151027A
  53. GRB 151111A: GROND marginal detection of a afterglow candidate
  54. GRB 151111A: LCOGT-FTS afterglow observations
  55. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  56. GRB 151107A: Further investigation of the source nature
  57. GRB 151107A: Swift detection of a possible burst
  58. GRB 151027A: GMG observation
  59. GRB 151027A: P60 afterglow confirmation and rebrightening
  60. LIGO/Virgo G194575: CQUEAN/LOAO observations
  61. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  62. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  63. LIGO Virgo G194575: TZAC TAROT observations
  64. Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
  65. Swift Trigger 657564: XRT prompt analysis
  66. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  67. LIGO/Virgo G184098: spectral classification of PS15cci
  68. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  69. GRB 150906B: Further analysis of the Konus-Wind data
  70. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  71. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  72. ANTARES neutrino detection and possible Swift X-ray counterpart
  73. GRB 150818A: possible SN rise in light curve of Mondy observations
  74. Swift Trigger 652046 is probably not a GRB
  75. GRB 150728A: FTN observations
  76. GRB 150720A: Swift-XRT refined Analysis
  77. Swift Trigger 649706: a possible GRB or bright Galactic transient
  78. Swift-XRT observations of GRB 150710A
  79. GRB 150710A: RATIR Observations
  80. Swift Trigger 648422: Swift-XRT observations
  81. Trigger 648422: Swift possible detection of a source in NGC4552
  82. Swift Trigger 645340: a possible GRB
  83. V404 Cyg: Fermi GBM observations
  84. GRB 150518A: possible SN observations
  85. Swift trigger 642453 is not an astrophysical source
  86. Swift Trigger 642453: a possible GRB
  87. GRB 150518A: MAXI-GSC further analysis
  88. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  89. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  90. GRB 150518A: SAO RAS optical observations
  91. Swift Trigger 639636: a possible GRB
  92. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  93. GRB150418A: Swift/UVOT did not detect a new source
  94. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  95. GRB 150407A: optical observations
  96. GRB 150407A: Swift detection of a possible burst
  97. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  98. GRB 150323C: additional optical observations in Mondy
  99. GRB 141121A: GMG observation
  100. GRB 150323C: possible host galaxy detection

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