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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"

20955 results found.

  1. GRB 141104A: further Swift-XRT observations and afterglow candidate
  2. GRB 141109A: VLA detection
  3. Trigger 618634: Swift detection of Vela X-1
  4. GRB 141015A: TAROT La Silla observatory optical observations
  5. GRB 141022A: TAROT La Silla observatory optical observations
  6. GRB 141031A: TAROT La Silla observatory optical observations
  7. GRB 141109A: TAROT La Silla observatory optical observations
  8. GRB 141109A: AAO optical observations
  9. Swift Trigger 618391 is not an astrophysical event
  10. GRB 141109B: Swift/UVOT Upper Limits
  11. GRB 141109A: Swift/UVOT Detection
  12. GRB 141109B: IRAM 30m millimetre observations
  13. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  14. GRB 141109A: GROND afterglow observation
  15. X-shooter redshift of GRB 141109A
  16. GRB 141109A: REM NIR candidate afterglow
  17. GRB 141104A: Swift-XRT observations
  18. GRB 141028A: Mondy optical observations
  19. GRB 141104A Tiled Swift observations
  20. GRB 141026A: Gemini-North optical and NIR imaging
  21. GRB 141031B: TShAO optical observations
  22. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  23. GRB 141022A: Skynet PROMPT-CTIO Observations
  24. GRB 141026A: VLA observations
  25. GRB 141031B: Swift/UVOT Upper Limits
  26. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  27. GRB 141031B: Bassano Bresciano Observatory upper limit
  28. GRB 141031B: NOT optical observations
  29. GRB 141031A: Swift/UVOT Upper Limits
  30. GRB 141031B: 1.23m CAHA I-band observations
  31. GRB 141031A: Skynet PROMPT-CTIO Observations
  32. GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
  33. GRB 141031A: VLT/X-shooter optical observations
  34. GRB 141031B: MASTER early optical observations
  35. GRB 141031A: GROND detection of a possible optical afterglow candidate
  36. GRB 141028A: SAO RAS Zeiss-1000 photometry
  37. GRB 140509A: GROND afterglow detection
  38. GRB 141028A: Continued RATIR Observations
  39. GRB 141028A: Swift/UVOT followup observations
  40. GRB 141028A: P60 Observations and Decay Index
  41. GRB 141028A: Swift-XRT observations
  42. GRB 141028A: LCOGTN observations
  43. GRB 141029A Tiled Swift observations
  44. GRB 141028A: VLT/X-shooter redshift of z=2.33
  45. GRB141028A: Gemini-North redshift
  46. GRB 141028A: RATIR Optical and NIR Observations
  47. GRB 141028A: Swift/UVOT Detection
  48. GRB 141028A: Swift/XRT detection of the X-ray afterglow
  49. GRB 141028A: GROND Afterglow confirmation (MASTER source)
  50. GRB 141020A: Continued Mondy Observations, optical upper limit
  51. GRB 141026A: IRAM 30m millimetre observations
  52. GRB 141028A Tiled Swift observations
  53. GRB 141028A: MASTER OT candidate detection
  54. GRB 141026A: Continued RATIR Optical and NIR Observations
  55. GRB 141026A: GTC spectroscopy
  56. GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
  57. GRB 141026A: SAO RAS Zeiss-1000 observations
  58. GRB 141026A: Continued RATIR Optical and NIR Observations
  59. GRB 141026A: Swift/UVOT Upper Limits
  60. GRB 141004A: Continued RATIR Late Time Optical and NIR Observations
  61. GRB 141026A: Continued RATIR Optical and NIR Observations, Afterglow Detection
  62. GRB 141026A: MASTER early optical observations
  63. GRB 141026A: 1.23m CAHA I-band observations
  64. GRB 141026A: GROND observations
  65. GRB 141026A: RATIR Optical Observations
  66. GRB 141026A: P60 early observations
  67. GRB 141022A: Swift/UVOT Upper Limits
  68. GRB 141020A: Mondy optical observations
  69. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  70. GRB 141004A: RATIR Late Time Optical and NIR Observations
  71. GRB 141004A: La Palma late-time observations and possible brightening
  72. GRB 141020A: Swift/UVOT Detection
  73. GRB 141017A: GROND Afterglow Confirmation
  74. GRB 141015A: Swift-XRT afterglow confirmation and refined Analysis
  75. GRB 141017A: Swift/UVOT Detection
  76. GRB 141017A: Zadko observatory - Gingin optical observations
  77. GRB 141015A: Swift/UVOT Upper Limits
  78. GRB 141015A: LCO-McDonald observations
  79. GRB 141015A: Super-LOTIS early observations
  80. GRB 141015A: ISON-NM early optical observations
  81. GRB 141005A: Additional P60 imaging and afterglow confirmation
  82. GRB 141004A: GROND observations
  83. GRB 141005A: GROND observations
  84. GRB 141005A: Swift/UVOT Upper Limits
  85. GRB141004A: NOT imaging and spectroscopy
  86. GRB 141004A: Swift/UVOT Detection
  87. GRB 141004A: RATIR Optical Observations
  88. GRB 141004A: Monte Agliale Observatory optical observations
  89. GRB 141005A: RATIR Optical Observations
  90. GRB 141005A: P60 probable afterglow deteaction
  91. GRB 141004A: TNG photometric and spectroscopic observations
  92. GRB 141004A: 1.23m CAHA optical observations
  93. Swift observations of HD 305560
  94. GRB 140928A: Swift-XRT follow-up observations
  95. GRB 140930B: Gemini South Spectroscopy
  96. GRB 140930B: GROND observations
  97. GRB 140930A/MAXI J2259+524: MASTER optical observations
  98. GRB 140930B: Swift/UVOT Upper Limits
  99. GRB 140930B: MMT confirmation of the optical afterglow
  100. GRB 140930B: ISON-Kislovodsk observations

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