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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"

23637 results found.

  1. GRB021004, late-time optical observations
  2. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  3. IPN triangulation of SGR1900+14, October 22 2002
  4. GRB 021004: optical observations
  5. GRB 020813; likely host galaxy.
  6. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  7. GRB 021016, optical observations
  8. GRB 021004: VRI observations at TNG: possible break
  9. SGR1900+14: burst on October 10 2002
  10. GRB021016(=H2397): A Long GRB Localized by HETE
  11. GRB021004: High-resolution optical spectroscopy
  12. IPN triangulation of GRB021013 (annulus)
  13. GRB021004: Optical Observations
  14. GRB021004 Chandra HETG Observations
  15. GRB 021004: WC wind?
  16. IPN triangulation of GRB021007 (annulus)
  17. XRF 020903 spectrum
  18. GRB021004: optical observations and predicted break time
  19. GRB021004: BVRc photometry
  20. GRB 021004: Optical Decay
  21. GRB 021004 continued IR fading
  22. HETE fluences for GRB021004
  23. GRB021004: not fading anymore?
  24. GRB021004: Update Bisei photometric data
  25. GRB021004: continued fading
  26. GRB 021004, optical observations
  27. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  28. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  29. GRB021004: Optical Afterglow
  30. GRB020924 (ecliptic latitude-only localization)
  31. IPN annulus for GRB020914B
  32. IPN triangulation of GRB020914
  33. IPN GCN Circulars now to be issued without restriction
  34. GRB020322 : HST/STIS observations
  35. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  36. INTEGRAL GRBs added to GCN
  37. GRB020812: optical observation
  38. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  39. SGR1900+14 burst localized by HETE
  40. GRB020813: High-resolution optical spectroscopy
  41. GRB020819: optical observations at Bisei
  42. Second epoch K band imaging of GRB 020819
  43. Confirming no variability for GRB02081
  44. GRB 020812: early time optical observation at Ouda Station
  45. GRB020813: VRI Decay Slopes
  46. K band observation of GRB 020819
  47. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  48. GRB020813: Fading X-ray Afterglow Observed with Chandra
  49. GRB 020813: addendum to GCN 1498
  50. GRB020813: optical observations at Bisei
  51. GRB020813: V-band decay slope
  52. GRB020813 IRAM millimeter observations
  53. GRB020812: optical observations
  54. GRB020813: High-Resolution Optical Observations
  55. GRB020813(=H2262): Revised Localization with HETE SXC
  56. GRB 020812: optical observation at Bisei
  57. GRB020813: Early Time Magnitude
  58. GRB 020812 : optical afterglow candidate
  59. IPN triangulation of GRB020813
  60. Early Time Limits for GRB020813
  61. GRB 020813 Afterglow Observations; Possible break
  62. GRB020813: Fading of Candidate OT
  63. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  64. GRB020813: Candidate Optical Afterglow
  65. GRB 020812 optical observation
  66. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  67. GRB 020715, optical observations
  68. GRB 020714, optical observations
  69. HST Imaging of the Host of GRB 011121
  70. GRB020331: Late-time Optical Light Curve (re-submission)
  71. GRB020331: Late-time Optical Light Curve
  72. GRB 020405: HST observations reveal red bump
  73. IPN triangulation of GRB020714
  74. GRB 020410: Discovery of Probable OT by HST
  75. GRB 020625, optical observations
  76. GRB020625 (=H2081): A Long Burst Localized by HETE
  77. GRB/XRF 020427, detection of an underlying system with the VLT
  78. Fading Optical Source in the Field of GRB020531
  79. GRB 020531, INT+WFC deep optical upper limits
  80. GRB 020604, optical observations
  81. GRB020604, BVRcIc field photometry
  82. GRB020531 Optical observations with TAROT
  83. GRB 020418, optical/near-IR observations
  84. GRB 020603, R-band observation
  85. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  86. GRB 020531 optical observations with TAROT
  87. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  88. IPN detection of possible bursts from SGR1806-20
  89. HST detection of the likely host galaxy of GRB 020124
  90. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  91. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  92. XRF 020427
  93. The end of BSAX GRB activities
  94. GRB 020124: Optical observations
  95. Mars Odyssey joins the IPN
  96. GRB020405: predicted break
  97. GRB 020409: No Evidence for an Optical Afterglow
  98. GRB 020409, 2nd epoch optical observations
  99. GRB 020331 Kyoto observation on March 31
  100. GRB 020409, No Optical Detection to R = 20

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