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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"

20531 results found.

  1. GRB 180618A: Swift/UVOT Detection
  2. GRB 180620A: Swift/UVOT Detection
  3. GRB 180620A: LCO McDonald observations
  4. GRB 180620A: MASTER OT observation
  5. GRB 180620A: RATIR Optical Afterglow Detection
  6. GRB 180618A: MASTER OT observation (a short GRB with extended emission)
  7. GRB 180618A: LT prompt observations
  8. GRB 180614A: AbAO optical observations
  9. GRB 180614A: Swift/UVOT Upper Limits
  10. GRB 180614A: NOT optical upper limits
  11. GRB 180614A: MASTER observation
  12. GRB 180613A: Swift/UVOT Upper Limits
  13. GRB 180613A GROND observations: correction
  14. GRB 180613A GROND observations
  15. GRB 180613A: Possible IR afterglow
  16. GRB 180613A: Possible host galaxy at XRT position, or star
  17. GW170817/GRB170817A: LBT optical detection
  18. GRB 180602A: Swift/UVOT Upper Limits
  19. GRB180523B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 548793993)
  20. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  21. GRB 180514A: Swift/UVOT Upper Limits
  22. GRB 180514A: 1.5m OSN optical observations
  23. GRB 180514A: GOTO Optical Observations
  24. GRB 180512A: VLT/HAWK-I NIR Observations
  25. GRB 180514A: Swift detection of a burst
  26. GRB 180512A: RATIR Optical Observations
  27. GRB 180512A: LBT optical detection
  28. GRB 180512A: Swift/UVOT Upper Limits
  29. GRB 180512A: LT prompt observations
  30. GRB 180512A: GROND upper limits
  31. GRB 180512A: NOT upper limits
  32. GRB 180512A: OASDG optical observations
  33. GRB 180512A: Upper limits from OSN
  34. GRB 180510A: Swift/UVOT followup observations
  35. GRB 180510B: VLT/X-shooter observations
  36. GRB 180510B: GROND detection in all bands
  37. GRB 180510B: TAROT La Silla observatory optical observations
  38. GRB 180418A: 15 GHz upper limits from AMI
  39. Chandra observations of GW170817 reveal a fading afterglow
  40. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  41. GRB 180504A: Swift/UVOT Upper Limits
  42. GRB 180504A: ePESSTO NTT NIR observations
  43. GRB 180504A: NOT afterglow candidate
  44. Swift Trigger 829046 is probably noise
  45. GRB 180425A: Swift/UVOT Upper Limits
  46. GRB 180418A: TAROT La Silla observatory early optical observations
  47. GRB 180418A : SQUEAN observations
  48. GRB 180418A: Further GROND observations
  49. GRB 180418A: Swift/UVOT Detection
  50. GRB 180418A: Continued RATIR Optical Observations
  51. GRB 180418A: Imaging of the optical afterglow with the 1.3 m DFOT and 3.6 m DOT in ARIES, India
  52. GRB 180418A GROND observations
  53. GRB 180418A: NOT optical observations
  54. GRB 180418A: Gemini-North imaging and spectroscopy
  55. GRB 180418A: 1.5m OSN optical observations
  56. GRB 180418A: RATIR Optical Observations
  57. LIGO/Virgo G299232: LOFAR follow-up
  58. GRB 180418A: Swift-XRT observations
  59. GRB 180418A: KAIT Optical Afterglow Candidate
  60. GRB 180409A: Swift-XRT afterglow detection
  61. GRB 180411A: Swift/UVOT Upper Limit
  62. GRB 180411A: Tautenburg observations
  63. GRB 180410A: RATIR Optical Observations
  64. GRB 180410A: Swift/UVOT Upper Limits
  65. GRB 180409A: Swift-XRT observations
  66. GRB 180409A: Tiled Swift observations
  67. Swift Trigger 823014: TAROT Calern observatory optical observations
  68. GRB 180404B: Swift/UVOT Detection
  69. Chandra observations of GRB161219B 400 days after the explosion
  70. GRB 180404A: Swift/UVOT Detection
  71. GRB 180404A: LCO FTS observations
  72. GRB 180404B: MASTER-OAFA OT observation
  73. GRB 180404A: MASTER-OAFA OT observation
  74. GRB 180404A: VLT/X-shooter redshift
  75. GRB 180402A: Swift/UVOT Upper Limits
  76. GRB 180402A: KAIT Optical Upper Limit
  77. GRB 180402A: LCO McDonald observations
  78. GRB 180331B: Swift/UVOT Upper Limits
  79. GRB 180331B: AbAO optical observations
  80. GRB 180329B: LCO FTS observations
  81. GRB 180331A: Swift/UVOT Upper Limits
  82. GRB 180329B: VLT/X-shooter spectroscopic observations
  83. GRB 180329B: Swift/UVOT Detection
  84. GRB 180329B: RATIR Optical Observations
  85. GRB 180329B: NOT optical afterglow detection
  86. GRB 180329A: Swift-BAT refined analysis
  87. GRB 180329B: Swift detection of a burst with an optical afterglow
  88. Swift Trigger 819301: possible GRB 180329A
  89. GRB 180325A: VLT/X-shooter spectroscopic observations
  90. GRB 180325A: further NOT observations
  91. GRB 180325A: Swift/UVOT Detection
  92. GRB 180325A: GROND observations
  93. GRB 180325A: Global MASTER-Net OT prompt observations
  94. GRB 180325A: TAROT Calern observatory optical observations
  95. GRB 180325A: RATIR Optical Observations
  96. GRB 180325A: prompt REM optical/NIR detection
  97. GRB 180325A: NOT redshift
  98. GRB 180325A: prompt LT observations
  99. GRB 180324A: Swift/UVOT Upper Limits
  100. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection

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