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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"

2803 results found.

  1. GRB 190202A: LCO-CTIO optical observations
  2. GRB 190129B: DDOTI Detection of the Possible Afterglow and Suggestion of Fading
  3. GRB 190129B: GROND possible host candidate
  4. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  5. GRB 190114C: GMRT detection at 1.26GHz
  6. Swift ToO Instructions Update
  7. Swift ToO Website Down
  8. GRB 190114C: RATIR Optical and NIR Detections
  9. GRB 190114C: COATLI Optical Detection
  10. GRB 190114B, Swift-BAT refined analysis
  11. GRB 190114C: SPI-ACS/INTEGRAL extended emission detection
  12. GRB 190114C: Possible host galaxy in Pan-STARRS
  13. GRB 190114B: Swift detection of a burst
  14. GRB 190114A: Possible UVOT Detection
  15. GRB 190106A: optical observations, possible jet break detection
  16. Correction to the GCN circ. 23654 / GRB 190109B: Mondy optical upper limit
  17. GRB 190106A: GMG spectral results
  18. GRB 181228A: possible NOT optical detection
  19. FRB 181228: Global MASTER Net optical inspection
  20. Swift Trigger 878504 is not astrophysical
  21. MASTER: OTs detection during Fermi alert trigger 565936249 early observations
  22. GRB 181201A: VLT/FORS2 tentative spectroscopic redshift
  23. Short-duration GRB 181121.4: MASTER-Tavrida possible OT detection near the PGC galaxy during large Fermi error box inspection
  24. GRB 181123B: Keck near-infrared imaging
  25. GRB 181110A: Kanata 1.5m optical observation
  26. Fermi GRB 181105.31: Global MASTER Net optical observations
  27. GRB 181030A: Swift detection of a burst with a possible optical counterpart
  28. IceCube-181023A - IceCube observation of a high-energy neutrino candidate event
  29. GRB 181020A: Global MASTER Net OT observations
  30. IceCube-181014A - IceCube observation of a high-energy neutrino candidate event
  31. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  32. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  33. GRB 180728A: discovery of the associated supernova
  34. Swift Trigger 852625: Swift/BAT/XRT/UVOT observations
  35. GRB 180809B: CALET Gamma-Ray Burst Monitor detection
  36. Swift Trigger 852625: a possible GRB
  37. GRB 180806.94: MASTER possible OT detection in Fermi GMB trigger 555287944 error box
  38. GMRT radio detection of GRB 180720B
  39. GRB 180728B: GOTO optical search over IPN region
  40. GRB 180728B: MASTER optical observations short GRB IPN error box
  41. GRB 180720C: Swift detection of a burst or possible Galactic Transient
  42. GRB 180720B: LCO Haleakala possible bright optical candidate
  43. GRB 180715A: LCO Sutherland possible optical candidate
  44. GRB 180705A: OSN observations
  45. Konus-Wind observation of GRB 180704A
  46. GRB 180703A: LCO Sutherland possible optical candidate
  47. GRB150101B: INTEGRAL prompt gamma-ray signal from a possible GRB170817A-analogue
  48. GRB 180626C : GOTO optical observations
  49. GRB 180626B : GOTO optical observations
  50. GRB 180613A: Possible IR afterglow
  51. GRB 180613A: Possible host galaxy at XRT position, or star
  52. GRB 180529A: CALET Gamma-Ray Burst Monitor detection
  53. AGILE/MCAL detection of GRB 180529 and a possible precursor
  54. Swift Trigger 831888: a possible GRB or Galactic transient
  55. GRB 180510B: Swift detection of a burst with an optical counterpart
  56. Chandra observations of GW170817 reveal a fading afterglow
  57. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  58. GRB 180418A GROND observations
  59. Chandra observations of GRB161219B 400 days after the explosion
  60. Swift Trigger 819301: possible GRB 180329A
  61. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  62. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  63. GRB 180224A: AbAO optical observations
  64. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  65. GRB180221A: MASTER-OAFA optical observations
  66. Swift Trigger 811074: possible GRB 180221A
  67. Trigger 809374: Swift detection of a possible non-burst faint source
  68. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  69. LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise ~156 Days Post-Merger
  70. GRB 180120A CALET Gamma-Ray Burst Monitor detection
  71. GRB180111A: Xinglong TNT possible optical detection
  72. GRB 180103A: LCO Sutherland 1-m telescope observations
  73. GRB 171209A: Swift/UVOT Analysis of the burst
  74. GRB 171209A: Swift detection of a burst
  75. LIGO/Virgo G298048: Brightening X-ray Emission from GW170817/GRB170817A/SSS17a
  76. LIGO/Virgo GW170817: Chandra X-ray brightening of the counterpart 108 days since merger
  77. GRB 171205A: Host galaxy photometric properties
  78. Possible blackbody component in the X-ray spectrum of GRB171205A
  79. Pan-STARRS follow-up of IceCube-171106A
  80. GRB 171123A: Swift detection of a burst
  81. GRB 171010A: possible SN component
  82. IceCube-171106A - IceCube observation of a high-energy neutrino candidate
  83. GRB 171030A: MASTER inspection of the IPN error box of the short GRB.
  84. GRB 171103A: Fermi GBM observation
  85. GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
  86. GRB 171030A: IPN error box through NSs probability merging rate map
  87. Swift trigger 781740: Further analysis from Swift and Fermi/GBM
  88. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  89. Swift trigger 779171 is probably a noise fluctuation
  90. IceCube-171015A - IceCube observation of a high-energy neutrino candidate event
  91. BAT trigger 778435 is not a GRB.
  92. GRB 171013A: Swift detection of a possible burst
  93. GRB 171010A: Swift/UVOT Detection
  94. GRB 171010A: ePESSTO NTT spectroscopic redshift
  95. GRB 171010A: OT, spectrum, and possible host galaxy
  96. LIGO/Virgo G298048: Mid-Infrared Spitzer/IRAC Observations at 3.6 and 4.5 microns
  97. Swift Trigger 775946 is a Galactic transient, not GRB 171003
  98. GRB 171003A: LT early optical observations
  99. GRB 170906C: 15 GHz upper limits from AMI
  100. LIGO/Virgo G298048: Summary of Pi of the Sky observations

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