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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"

24353 results found.

  1. GRB 021112: Variable Source in R-band search
  2. GRB021113: Kiso Observations
  3. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  4. GRB 021112: RAPTOR Observations
  5. GRB 021113: Optical Observations
  6. GRB021113 (=H2449): A Long GRB Localized by HETE
  7. GRB 021112: R-band search
  8. IPN triangulation of GRB021108 (large error box)
  9. GRB021112 (=H2448): A Long GRB Localized by HETE
  10. GRB021004: Near infrared spectroscopy
  11. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  12. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  13. SGR1900+14 activity, November 2-4, 2002
  14. GRB021104: optical observations
  15. GRB021104: possible optical afterglow
  16. Detection of activity from SGR 1900+14 with the RXTE/PCA
  17. GRB021004, late-time optical observations
  18. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  19. IPN triangulation of SGR1900+14, October 22 2002
  20. GRB 021004: optical observations
  21. GRB 020813; likely host galaxy.
  22. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  23. GRB 021016, optical observations
  24. GRB 021004: VRI observations at TNG: possible break
  25. SGR1900+14: burst on October 10 2002
  26. GRB021016(=H2397): A Long GRB Localized by HETE
  27. GRB021004: High-resolution optical spectroscopy
  28. IPN triangulation of GRB021013 (annulus)
  29. GRB021004: Optical Observations
  30. GRB021004 Chandra HETG Observations
  31. GRB 021004: WC wind?
  32. IPN triangulation of GRB021007 (annulus)
  33. XRF 020903 spectrum
  34. GRB021004: optical observations and predicted break time
  35. GRB021004: BVRc photometry
  36. GRB 021004: Optical Decay
  37. GRB 021004 continued IR fading
  38. HETE fluences for GRB021004
  39. GRB021004: not fading anymore?
  40. GRB021004: Update Bisei photometric data
  41. GRB021004: continued fading
  42. GRB 021004, optical observations
  43. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  44. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  45. GRB021004: Optical Afterglow
  46. GRB020924 (ecliptic latitude-only localization)
  47. IPN annulus for GRB020914B
  48. IPN triangulation of GRB020914
  49. IPN GCN Circulars now to be issued without restriction
  50. GRB020322 : HST/STIS observations
  51. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  52. INTEGRAL GRBs added to GCN
  53. GRB020812: optical observation
  54. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  55. SGR1900+14 burst localized by HETE
  56. GRB020813: High-resolution optical spectroscopy
  57. GRB020819: optical observations at Bisei
  58. Second epoch K band imaging of GRB 020819
  59. Confirming no variability for GRB02081
  60. GRB 020812: early time optical observation at Ouda Station
  61. GRB020813: VRI Decay Slopes
  62. K band observation of GRB 020819
  63. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  64. GRB020813: Fading X-ray Afterglow Observed with Chandra
  65. GRB 020813: addendum to GCN 1498
  66. GRB020813: optical observations at Bisei
  67. GRB020813: V-band decay slope
  68. GRB020813 IRAM millimeter observations
  69. GRB020812: optical observations
  70. GRB020813: High-Resolution Optical Observations
  71. GRB020813(=H2262): Revised Localization with HETE SXC
  72. GRB 020812: optical observation at Bisei
  73. GRB020813: Early Time Magnitude
  74. GRB 020812 : optical afterglow candidate
  75. IPN triangulation of GRB020813
  76. Early Time Limits for GRB020813
  77. GRB 020813 Afterglow Observations; Possible break
  78. GRB020813: Fading of Candidate OT
  79. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  80. GRB020813: Candidate Optical Afterglow
  81. GRB 020812 optical observation
  82. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  83. GRB 020715, optical observations
  84. GRB 020714, optical observations
  85. HST Imaging of the Host of GRB 011121
  86. GRB020331: Late-time Optical Light Curve (re-submission)
  87. GRB020331: Late-time Optical Light Curve
  88. GRB 020405: HST observations reveal red bump
  89. IPN triangulation of GRB020714
  90. GRB 020410: Discovery of Probable OT by HST
  91. GRB 020625, optical observations
  92. GRB020625 (=H2081): A Long Burst Localized by HETE
  93. GRB/XRF 020427, detection of an underlying system with the VLT
  94. Fading Optical Source in the Field of GRB020531
  95. GRB 020531, INT+WFC deep optical upper limits
  96. GRB 020604, optical observations
  97. GRB020604, BVRcIc field photometry
  98. GRB020531 Optical observations with TAROT
  99. GRB 020418, optical/near-IR observations
  100. GRB 020603, R-band observation

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