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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"

20967 results found.

  1. GRB021004: High-resolution optical spectroscopy
  2. XRF 020903: flattening of the optical light curve.
  3. GRB021004: Optical Observations
  4. GRB 021004 submm observations
  5. GRB021004 Chandra HETG Observations
  6. GRB 021004: Optical/NIR Observations
  7. GRB 021004: Additional V-band Polarimetric Observations
  8. GRB 021004 submm observations
  9. GRB 021004: WC wind?
  10. GRB021004: NIR and Optical observations
  11. GRB 021004: Optical observations, AUDE network
  12. GRB 021004 - VLA Radio Observations
  13. GRB 021004 - Unusual Radio-to-Submm Spectrum
  14. GRB 021004: optical spectroscopy
  15. GRB 021004: HST/STIS spectroscopic observations
  16. GRB021004: optical observations and predicted break time
  17. GRB021004: BVRc photometry
  18. GRB 021004: Optical Decay
  19. GRB 021004 continued IR fading
  20. GRB 021004, spectroscopic observations
  21. GRB 021004: polarimetric observations
  22. GRB 021004: V-band Polarimetric Observations
  23. GRB021004: Update Bisei photometric data
  24. GRB 021004: Optical Decay
  25. GRB021004, Optical Observations
  26. GRB 021004: Optical observations at RIKEN
  27. GRB 021004: Optical Observations
  28. GRB021004: continued fading
  29. GRB 021004: Optical Photometry at 1.5 Days
  30. GRB021004, Optical Observations
  31. GRB 021004: Optical observations
  32. GRB 021004, optical observations
  33. GRB021004: Optical Spectroscopy
  34. GRB 021004: Optical Observations
  35. GRB 021004, SPM optical observations
  36. GRB 021004, optical observations
  37. GRB 021004: radio observations
  38. GRB 021004: steepening of the optical decay slope
  39. GRB021004: Upper limits from recent and historical observations
  40. GRB021004: optical observations at Nyrola
  41. GRB021004: optical observations at Bisei
  42. GRB021004: Optical Afterglow
  43. XRF020903: TNG and Asiago photometry
  44. GRB 020903: Optical observations at RIKEN
  45. XRF 020903: Correction to GCN 1560
  46. XRF 020903: VRI observations
  47. GRB 020903: correction to GCN 1557
  48. XRF 020903: R band observations
  49. XRF 020903: Archival Optical Images
  50. Radio Observations of XRF 020903: The Missing Link
  51. XRF 020903: Supernova
  52. GRB 020305: HST/STIS observations
  53. GRB020322 : HST/STIS observations
  54. XRF 020903: Optical observations
  55. XRF 020903: Optical observations
  56. XRF 020903, optical observations
  57. GRB020813: High-resolution optical spectroscopy
  58. GRB020819: optical observations at Bisei
  59. GRB020812: negative optical observations
  60. GRB020813, Baade 6.5m data now available
  61. GRB 020813 : HST observations
  62. Confirming no variability for GRB02081
  63. GRB020819 : Optical observations at KISO
  64. GRB020813: VRI Decay Slopes
  65. GRB020813: Magellan BVRI Photometry
  66. GRB 020819: Optical observations
  67. K band observation of GRB 020819
  68. GRB020819: optical observations
  69. HETE 2275: Optical observations
  70. GRB020813: optical and NIR observations
  71. GRB020813: Fading X-ray Afterglow Observed with Chandra
  72. GRB020813: optical observations at Bisei
  73. GRB020812: NIR observations
  74. Polarimetry of GRB020813: evidence for variability
  75. GRB020813 IRAM millimeter observations
  76. GRB020812: optical observations
  77. GRB020813: High-Resolution Optical Observations
  78. GRB 020812: optical observation at Bisei
  79. GRB020813: optical observations; possible host galaxy
  80. GRB 020813, radio detection
  81. GRB 020812 : optical afterglow candidate
  82. GRB020813, optical observations
  83. Millimeter observation of GRB 020813
  84. GRB020812: optical observations
  85. GRB 020813 : KISO multiband optical observations
  86. GRB020813, optical observations
  87. GRB 020813 Afterglow Observations; Possible break
  88. GRB 020813 multiband optical observations
  89. GRB020813: Fading of Candidate OT
  90. GRB 020715, optical observations
  91. GRB 020714, optical observations
  92. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  93. GRB020801: Candidate OT present in DSS
  94. GRB020801, optical afterglow candidate
  95. GRB020331: Late-time Optical Light Curve (re-submission)
  96. GRB020331: Late-time Optical Light Curve
  97. GRB 020405: HST observations reveal red bump
  98. GRB 020410: Discovery of Probable OT by HST
  99. GRB 020124, HST observations of the fading afterglow
  100. GRB 020705: Optical observations

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