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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"

20571 results found.

  1. GRB 161214B: RATIR Optical and Near-Infrared Observations
  2. GRB 161214B: TAROT Calern observatory optical observations
  3. GRB 161214B: Chante-perdrix observatory optical observations
  4. GRB 161214B: Swift/UVOT Observations
  5. GRB 161214B: NOT optical observations, possible counterpart
  6. GRB 161214A: NOT observations of the afterglow
  7. GRB 161214A: GROND afterglow observations
  8. GRB 161214A: TAROT Calern observatory optical observations
  9. INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161210
  10. GRB 161129A: GTC redshift of the likely host galaxy
  11. GRB 161129A: NOT optical observations and candidate host galaxy
  12. GRB 161129A: KWFC z-band photometry
  13. MASTER: Optical Blazar Flare Detection during Fermi trigger 502272781 inspection
  14. GRB 161202A: RATIR Optical and NIR Observations
  15. GRB 161202A: Swift/UVOT Upper Limits
  16. GRB 161129A: Mondy optical observations
  17. GRB 161129A: ISON/UAFO optical observations
  18. GRB 161129A: MITSuME Okayama Ks-band Observation
  19. GRB 160821B: HST detection of the optical and IR counterpart
  20. GRB 161129A: Swift/UVOT Detection
  21. GRB 161129A: Tautenburg Ic-band observations
  22. GRB 161129A: TSHAO optical observations / possible afterglow+host galaxy
  23. GRB 161123A: Swift-XRT observations
  24. GRB 161123A: Tiled Swift observations
  25. GRB 161117A: SMARTS optical/IR afterglow observations
  26. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  27. GRB 161108A: 15 GHz upper limits from AMI
  28. GRB 161117A: MASTER-OAFA (Argentina) prompt OT observations
  29. GRB 161117A: TAROT La Silla observatory optical observations
  30. GRB 161117A: GMG observation limit
  31. GRB 161117B: Swift/UVOT Upper Limits
  32. GRB 161117A: Swift/UVOT Detection
  33. GRB 161117B: LCO optical observations
  34. GRB161117A: REM optical and NIR afterglow detection
  35. GRB 161113A: Swift/UVOT Upper Limits
  36. GRB 161113A: RATIR Optical and NIR Observations
  37. GRB 161109A: Swift/UVOT Upper Limits
  38. GRB 161104A: Magellan imaging and spectroscopy
  39. GRB 161108A: continued TSHAO optical observations
  40. GRB 161104A: Chandra X-ray observations
  41. GRB 161109A: Swift-XRT observations
  42. GRB 161108A: TSHAO optical observations
  43. GRB 161108A: Swift/UVOT Upper Limits
  44. GRB 161109A: Tiled Swift observations
  45. GRB 161105A: Swift/UVOT Upper Limits
  46. GRB 161108A: TAROT Calern observatory optical observations
  47. GRB 161105A: TAROT La Silla observatory optical observations
  48. GRB 161108A: NOT redshift
  49. GRB 161108A: NOT candidate afterglow
  50. Fermi LAT Gamma-ray Observations of IceCube-161103
  51. GRB 161022A: 15 GHz upper limits from AMI
  52. GRB 161017A: 15 GHz upper limits from AMI
  53. GRB 161104A: Gemini South optical observations
  54. GRB 161105A: MASTER-IAC early optical observations
  55. GRB 161104A: GROND observations
  56. GRB 161104A: Swift/UVOT Upper Limits
  57. Fermi GBM Observations of IceCube-161103
  58. IceCube-161103: Swift-XRT observations
  59. INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161103
  60. IceCube-161103: MASTER follow-up observations
  61. GRB 161015A: 15 GHz upper limits from AMI
  62. GRB 161014A: 15 GHz upper limits from AMI
  63. GRB 161023A: GROND Observations
  64. GRB 161023A: Swift-XRT afterglow detection
  65. GRB 161023A: TAROT La Silla observatory optical observations
  66. GRB 161023A: Zadko observatory - Gingin optical observations
  67. GRB 161023A: Watcher optical observations
  68. GRB 161023A: LCOGT-FTS optical observations
  69. GRB 161023A: Swift ToO observations
  70. Radio upper limit on the GRB 161011A with the GMRT
  71. GRB 161023A VLT/X-shooter redshift
  72. Swift Trigger 718919 is not an astrophysical event.
  73. GRB 161022A: RATIR Optical and NIR Observations
  74. GRB 161022A: Swift/UVOT Upper Limits
  75. GRB 161022A: NOT optical observations
  76. GRB 161022A: LT observations
  77. GRB 161022A: TAROT Calern observatory optical observations
  78. GRB 161015A: further Swift-XRT follow-up observations
  79. GRB 161011A: 15 GHz upper limits from AMI
  80. GRB 161007A: 15 GHz upper limits from AMI
  81. GRB161017A: NOEMA detection of the millimetre afterglow
  82. GRB 161017A: LT optical observations
  83. GRB161017A optical R band observations with SARA-RM
  84. GRB 161017A: TNG spectroscopy and redshift confirmation
  85. GRB 161017A: Lomonosov Gamma Ray and MASTER Optical prompt observations
  86. GRB 161017A: Swift/UVOT Detection
  87. GRB161017A: optical observations with 1-m LCOGT McDonald
  88. GRB 161017A: TNG optical observations
  89. GRB 161017A: Redshift from GTC
  90. GRB 161014A: Continued RATIR Optical and NIR Observations
  91. GRB 161015A: Swift/UVOT observations
  92. GRB 161014A: VLT/X-shooter redshift confirmation
  93. GRB 161014A: refined analysis of TSHAO optical observations
  94. GRB 161015A: Swift-XRT observations
  95. GRB 161015A: Tiled Swift observations
  96. GRB 161014A: RATIR Optical and NIR Observations
  97. GRB 161014A: TNG optical observations
  98. GRB 161014A: Swift/UVOT Detection
  99. GRB161014A: NOT optical observations
  100. GRB 161014A: GTC spectroscopy

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