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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"

2747 results found.

  1. GRB 161004A: Swift detection of a burst with a possible optical counterpart
  2. Possible radio detection of GRB 160910A with the GMRT
  3. GRB 160925A: Bassano Bresciano Photometry of MASTER optical transient
  4. GRB 160925A: Optical spectroscopy of MASTER optical transient
  5. GRB 160816A: Possible radio afterglow detection at 15 GHz with AMI
  6. IceCube HESE 160814: MASTER OT J130845.02-323254.9 as the possible source of the high energy neutrino
  7. GRB 160816A, the review of the sky area in plate archives
  8. GRB 160825A: not localized by Swift
  9. GRB 160824A: Swift/UVOT Possible Afterglow Detection
  10. Possible radio detection of GRB160703A with the GMRT
  11. Possible radio detection of GRB160623A with the GMRT
  12. GRB 160821A: Swift-BAT refined analysis
  13. GRB 160816A: MASTER inspection
  14. IceCube 160806A EHE Neutrino Candidate Event
  15. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  16. GRB160804A: MASTER-SAAO observation
  17. Global MASTER net follow up of IceCube-160731A
  18. Swift Trigger 704327: KAIT Optical Observations
  19. Swift Trigger 704444 is probably not an astrophysical event.
  20. Swift Trigger 704327: MASTER syncronous optical observations
  21. Swift Trigger 704327: a possible GRB
  22. GRB 160712A: Swift/UVOT Upper Limits
  23. SGR 1935+2154: CALET Gamma-Ray Burst Monitor detections
  24. GRB 160705B: Swift-BAT refined analysis
  25. GRB 160623A: Possible detection of a radio afterglow at 15 GHz with AMI
  26. GRB 160624A: Lulin observation
  27. GRB160624A:possible GRB host redshift
  28. Fermi GBM Trigger 160622573 is not a GRB
  29. BAT trigger 700791 (possible GRB 160622A) is SNR RCW 103
  30. GRB 160622A: Swift detection of a possible short GRB or a new SGR
  31. Trigger 689956: Swift detection of a source near the Galactic center
  32. Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
  33. GRB 160530A: discovery with the Compton Spectrometer and Imager
  34. GRB 160525A: Swift-BAT refined analysis
  35. GRB 160521B: Theoretical estimate of the redshift and urgent need for further x-ray observations
  36. GRB 160425A: SMARTS late-time observations
  37. GRB 160521B: Swift/UVOT Upper Limits
  38. Fermi GBM triggers of SGR 1935+2154
  39. Interplanetary Network Search for IceCube 160427A
  40. GRB 160509A Gemini North redshift
  41. IceCube-160427A: iPTF Observations
  42. GRB 160417A, the review of the sky area in plate archive
  43. ICECUBE-160427A neutrino candidate event: updated direction information
  44. GRB 160425A MASTER notices: possible host galaxy in the optical error-box
  45. GRB 160409A found in Swift BAT ground analysis
  46. GRB 160408A: TLS Tautenburg observations
  47. GRB 160408A: Swift/UVOT Upper Limits
  48. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  49. GRB 160321A: Possible RATIR Optical and NIR Detections
  50. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  51. GRB 160310A: Swift/UVOT Upper Limits
  52. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  53. GRB 160307A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  54. GRB 160310A: NOT optical observations
  55. GRB 160303A: GTC imaging of possible host galaxy
  56. GRB 160303A: Observations from T150 OSN
  57. GRB 160303A: McDonald 2.1m CQUEAN Detection
  58. GRB160228A: Further analyses on spectral lag and extended emission
  59. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  60. GRB 160223B: Khureltogot optical observations
  61. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  62. GRB 160131A: second epoch observations with the GMRT
  63. Low frequency GMRT observations of GRB 160131A
  64. GRB 160131A: RATIR Optical Observations
  65. LIGO/Virgo G211117: MASTER OTs 26.XII.2015 - 01.I.2016
  66. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  67. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  68. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  69. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  70. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  71. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  72. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  73. GRB 151122A: Swift detection of a burst
  74. Swift Trigger 664610: is unlikely a GRB
  75. 610 MHz detection of GRB 151027A with the GMRT
  76. GMRT radio detection of GRB 151027A
  77. GRB 151111A: GROND marginal detection of a afterglow candidate
  78. GRB 151111A: LCOGT-FTS afterglow observations
  79. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  80. GRB 151107A: Further investigation of the source nature
  81. GRB 151107A: Swift detection of a possible burst
  82. GRB 151027A: GMG observation
  83. GRB 151027A: P60 afterglow confirmation and rebrightening
  84. LIGO/Virgo G194575: CQUEAN/LOAO observations
  85. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  86. LIGO/Virgo G194575: Mini-MegaTORTORA observations
  87. LIGO Virgo G194575: TZAC TAROT observations
  88. Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
  89. Swift Trigger 657564: XRT prompt analysis
  90. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  91. LIGO/Virgo G184098: spectral classification of PS15cci
  92. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  93. GRB 150906B: Further analysis of the Konus-Wind data
  94. ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source
  95. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  96. ANTARES neutrino detection and possible Swift X-ray counterpart
  97. GRB 150818A: possible SN rise in light curve of Mondy observations
  98. Swift Trigger 652046 is probably not a GRB
  99. GRB 150728A: FTN observations
  100. GRB 150720A: Swift-XRT refined Analysis

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