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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"

20968 results found.

  1. GRB 061004: Further VLT/NTT observations
  2. GRB061102B: Super-LOTIS observations
  3. GRB 061028: Optical R passband observations
  4. GRB 060801: Swift/XRT Astrometry Correction
  5. GRB 061028: Futher P200 Observations
  6. GRB 061028: MDM Observations
  7. GRB 061028: P200 Observations
  8. GRB 061028: SARA upper limit
  9. GRB 061028: Swift/UVOT Observations
  10. GRB 061028: TAROT Calern observatory late optical observations
  11. GRB 061028: TAROT Calern observatory optical observations
  12. GRB061025: Swift/UVOT observations
  13. GRB 061025: REM observations
  14. GRB 061025: Gemini-S observations
  15. GRB061025: Swift XRT position
  16. GRB 061021 - VLT spectrum without lines
  17. GRB 061021: Swift/UVOT Observation
  18. GRB 061019: Super-LOTIS upper limit
  19. GRB060904b: optical observations
  20. GRB061019: optical observations
  21. GRB061019: optical observations
  22. GRB 061019: SMARTS afterglow confirmation
  23. GRB 061019: TAROT La Silla observatory optical observations
  24. GRB 061019: REM K-band candidate afterglow
  25. GRB061019: Swift/XRT position
  26. GRB 060825: GORT Observations
  27. GRB 061007: Second Epoch ATCA Radio Observations
  28. GRB 061006: astrometry-corrected XRT position
  29. GRB 061007: ATCA Radio Observations
  30. GRB061007: Swift UVOT followup observations
  31. GRB 061006: optical afterglow
  32. GRB 061007: Magellan Spectroscopy
  33. GRB 061006: Swift/UVOT optical observations
  34. GRB 061007 - FTS early brightening and power law decay
  35. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  36. GRB 061007: ROTSE-III Detection of Optical Counterpart
  37. GRB 061006: VLT observation
  38. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  39. GRB061006: Faulkes Telescope South Observations
  40. GRB 061004: Las Campanas Optical/NIR Observations
  41. GRB061004: Swift/UVOT optical observations
  42. GRB 060928: Swift observations
  43. GRB061002: Swift UVOT followup observations
  44. VLA observations of GRB 060926
  45. GRB061002 - SDSS Pre-Burst Observations
  46. GRB061002: MASTER-VWF-Kislovodsk observations
  47. GRB 060923A: VLA K-band Observations
  48. GRB 060930: Xinglong TNT optical observations
  49. GRB 060929: Swift/UVOT Optical Observations
  50. GRB 060929: TNG K-band observations
  51. GRB 060929: MASTER-VWF-Kislovodsk observations
  52. GRB 060929: BOOTES-IR & OSN observations
  53. Liverpool Telescope observations of GRB 060929
  54. GRB060908: optical observations
  55. GRB 060729: An update on the late-time Swift observations
  56. GRB060927: optical observations
  57. GRB 060927: Swift/UVOT Optical Observations
  58. GRB 060927: Xinglong TNT optical observations
  59. GRB 060927 : Kiso optical observation
  60. GRB060927: Faulkes Telescope South observation
  61. GRB 060926: MASTER: first minutes decay
  62. GRB060927 - SDSS Pre-Burst Observations
  63. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  64. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  65. GRB 060926: OPTIMA-Burst -- further observations
  66. GRB 060923A: Radio Observations
  67. GRB 060926: MASTER OT alert observation
  68. GRB 060912A: Redshift of probable host galaxy
  69. GRB 060926: BOOTES-IR observations
  70. GRB 060926: Watcher observations
  71. GRB 060923C: Gemini Observations and Afterglow Candidate
  72. GRB 060923C: VLT J-band observations
  73. GRB 060923C: Keck Observations
  74. GRB 060923A: Keck and Gemini Observations
  75. GRB 060923C: Xinglong TNT optical observations
  76. GRB060923C : Faulkes Telescope South optical limits
  77. GRB060923C: Faulkes Telescope North optical observations
  78. GRB 060923: Early Super-LOTIS Observations
  79. GRB 060923: UKIRT nIR observations - candidate afterglow
  80. GRB060923: Faulkes Telescope North optical observations
  81. GRB060923 - SDSS Pre-Burst Observations
  82. GRB 060923: KAIT observations
  83. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  84. GRB060919: Swift/UVOT optical observations
  85. GRB 060919 : Faulkes South Telescope Observations
  86. GRB 060919: TAROT optical observations
  87. GRB 060912A: Probable Host Galaxy
  88. GRB 060912: Redshift of nearby 2MASS galaxy
  89. GRB060912: optical observations
  90. GRB 060912B: Watcher observations
  91. GRB060912: Swift/UVOT Observations
  92. GRB060912: OPTIMA-Burst optical observations
  93. GRB 060912: Xinglong TNT optical observations
  94. GRB060906: Danish/DFOSC optical observations
  95. VLA observations of GRB 060908
  96. GRB 060908: redshift
  97. GRB 060908: Swift/UVOT Observations
  98. GRB 060908: Danish/DFOSC optical observations
  99. GRB 060908 - SDSS Pre-burst Observations
  100. GRB 060904B : CFHT/WIRCam NIR afterglow observations

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