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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"

14806 results found.

  1. GRB 141121A: RATIR Optical Observations - Fading Again
  2. GRB 141118A: Fermi GBM Detection
  3. GRB 141121A: Mondy optical observations
  4. GRB 141121A: LCO-FTN rebrightening confirmation
  5. GRB 141121A: MITSuME Ishigakijima Optical Observation
  6. GRB 141121A: MITSuME Akeno Optical observation
  7. GRB 141121A: RATIR Optical Observations
  8. GRB 141121A: GROND Afterglow candidate
  9. GRB 141121A: MAXI/GSC detection
  10. Konus-Wind observation of GRB 141118A
  11. GRB 141104A: further Swift-XRT observations and afterglow candidate
  12. GRB 141109A: TAROT La Silla observatory optical observations
  13. GRB 141109A: AAO optical observations
  14. Konus-Wind observation of GRB 141109A
  15. GRB141109A : Xinglong TNT optical observation
  16. GRB 141109A: MITSuME Ishigakijima upper limits
  17. GRB 141109A: CQUEAN Detection at 0.85 - 1.05 micron
  18. GRB 141109A: GROND afterglow observation
  19. X-shooter redshift of GRB 141109A
  20. GRB 141104A Tiled Swift observations
  21. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  22. Konus-Wind observation of GRB 141104A
  23. Konus-Wind observation of GRB 141102A
  24. GRB 141022A: Skynet PROMPT-CTIO Observations
  25. GRB 141102A: Fermi-LAT detection
  26. GRB 141102A: Fermi GBM detection
  27. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  28. GRB 141031A: Skynet PROMPT-CTIO Observations
  29. GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
  30. GRB 141031A: Fermi GBM detection
  31. GRB 141031A: GROND detection of a possible optical afterglow candidate
  32. GRB 141029A: Nanshan optical upper limit
  33. GRB 140509A: GROND afterglow detection
  34. GRB 141028A: Continued RATIR Observations
  35. GRB 141029B: Fermi GBM detection
  36. GRB 141029A Tiled Swift observations
  37. GRB 141028A: VLT/X-shooter redshift of z=2.33
  38. GRB 141028A: Swift/UVOT Detection
  39. GRB 141028A: GROND Afterglow confirmation (MASTER source)
  40. GRB 141020A: Continued Mondy Observations, optical upper limit
  41. GRB 141028A Tiled Swift observations
  42. GRB 141026A: Continued RATIR Optical and NIR Observations
  43. GRB 141028A: Fermi-LAT detection
  44. GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
  45. GRB 141004A: Continued RATIR Late Time Optical and NIR Observations
  46. GRB 141026A: Continued RATIR Optical and NIR Observations, Afterglow Detection
  47. GRB141026A: Deep P200 optical imaging
  48. GRB 141026A: 1.23m CAHA I-band observations
  49. GRB 141026A: GROND observations
  50. GRB 141026A: P60 early observations
  51. GRB 141020A: AAO optical upper limit
  52. GRB 141020A: Khureltogot optical upper limit
  53. GRB141022A: Fermi GBM Detection
  54. GRB 141020A: Mondy optical observations
  55. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  56. GRB 141004A: RATIR Late Time Optical and NIR Observations
  57. Konus-Wind observation of GRB 141017A
  58. GRB 141017A: GROND Afterglow Confirmation
  59. Konus-Wind observation of GRB 141011A
  60. GRB 141011A: Fermi GBM detection
  61. GRB141004A: Host galaxy redshift form GTC
  62. GRB 141005A: Additional P60 imaging and afterglow confirmation
  63. GRB 141004A: Fermi GBM observation
  64. GRB 141004A: GROND observations
  65. GRB 141005A: GROND observations
  66. Konus-Wind observation of GRB 141005A
  67. GRB 141005A: Swift/UVOT Upper Limits
  68. GRB141004A: NOT imaging and spectroscopy
  69. GRB 141005A: Fermi GBM Detection
  70. GRB 141004A: RATIR Optical Observations
  71. GRB 141005A: RATIR Optical Observations
  72. GRB 141004A: TNG photometric and spectroscopic observations
  73. Swift observations of HD 305560
  74. GRB 140928A: Swift-XRT follow-up observations
  75. Swift possible detection of the Be star HD 305560
  76. GRB 140930B: GROND observations
  77. Konus-Wind observation of GRB 140930B
  78. GRB 140930B: Keck NIR imaging
  79. Konus-Wind observation of GRB 140928A
  80. GRB 140928A: Fermi GBM detection
  81. GRB 140928A: Fermi-LAT detection
  82. GRB 140919A: Fermi GBM observation
  83. GRB 140916B: LOT and iPTF follow-up of optical afterglow candidates
  84. GRB 140909A: Confirmation of the Swift-XRT afterglow
  85. GRB 140903A: Chandra detection of the afterglow
  86. Konus-Wind observation of GRB 140906C
  87. GRB 140907A: MASTER optical observations
  88. GRB 140907A: MITSuME Akeno Optical Observation
  89. GRB 140907A: Fermi GBM Detection
  90. GRB 140907A: MITSuME Ishigakijima Optical Observation
  91. GRB140907A: MITSuME Okayama Optical Observation
  92. GRB 140906B: Fermi GBM Detection of a Long GRB
  93. GRB 140907A : Optical observations from Nanshan
  94. GRB 140906A - Fermi GBM Detection
  95. GRB 140903A: Possible optical variability
  96. GRB 140903A: NOT optical and NIR observations
  97. GRB 140903A: FTN observations
  98. GRB 140903A: 6 GHz VLA detection
  99. GRB 140903A: Pan STARRS images of the field
  100. GRB 140901B: Fermi GBM detection

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