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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"

11801 results found.

  1. GRB021004, Optical Observations
  2. GRB 021004, optical observations
  3. GRB 021004, SPM optical observations
  4. GRB 021004: steepening of the optical decay slope
  5. XRF020903, BVRI field photometry
  6. GRB 020903: Optical observations at RIKEN
  7. XRF 020903: Supernova
  8. IPN triangulation of GRB020926 (two large error boxes)
  9. GRB020924 (ecliptic latitude-only localization)
  10. IPN triangulation of GRB020923 (two error boxes)
  11. Improved IPN position for GRB020918 (two large error boxes)
  12. IPN triangulation of GRB020911 (2 large error boxes)
  13. IPN detection of a burst from SGR1900+14
  14. INTEGRAL GRBs added to GCN
  15. GRB020812: optical observation
  16. Second epoch K band imaging of GRB 020819
  17. GRB 020812: early time optical observation at Ouda Station
  18. GRB020813: Magellan BVRI Photometry
  19. GRB 020819 : OT candidate - confirmation of non variability
  20. K band observation of GRB 020819
  21. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  22. IPN triangulation of GRB020819 (HETE 2275)
  23. GRB020813: Fading X-ray Afterglow Observed with Chandra
  24. GRB020812: NIR observations
  25. GRB020812: optical observations
  26. GRB 020812 : optical afterglow candidate
  27. GRB020813, optical observations
  28. GRB 020812 optical observation
  29. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  30. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  31. GRB020801, optical afterglow candidate
  32. IPN triangulation of GRB020714
  33. GRB 020410: Discovery of Probable OT by HST
  34. Correction to IPN error box for GRB020706
  35. IPN triangulation of GRB020706
  36. GRB 020705: Optical observations
  37. GRB020625 (=H2081): A Long Burst Localized by HETE
  38. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  39. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  40. AXP 1E2259+586: quasi-simultaneous optical observation
  41. AXP 1E2259+586 optical observations
  42. SGR-like Bursts from the AXP 1E 2259+586
  43. GRB 020531, simultaneous optical observations
  44. GRB020531: Second epoch Chandra observations
  45. GRB020531: Observations with the Chandra X-ray Observatory
  46. GRB020531, optical observation
  47. IPN triangulation of the short, hard GRB020531 (=H2042)
  48. GRB020525, optical observations
  49. IPN detection of possible bursts from SGR1806-20
  50. IPN triangulation of GRB020525
  51. XRF 020427: Sudden Ionospheric Disturbance (SID)
  52. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  53. IPN triangulation of a burst from SGR1806-20
  54. GRB 020410, Radio Observations
  55. GRB 020124: Optical observations
  56. IPN triangulation of GRB020418
  57. GRB020410: BeppoSAX NFI observations refined analysis
  58. Mars Odyssey joins the IPN
  59. IPN triangulation of GRB020413
  60. GRB 020409 SARA Observations
  61. GRB 020409, No Optical Detection to R = 20
  62. GRB020410: BeppoSAX NFI observation
  63. GRB 020409, optical observations
  64. GRB020406(?), optical observations
  65. BeppoSAX ALERT: possible GRB020410
  66. GRB020331 optical observations with RIMOTS
  67. GRB020124 optical observations with RIBOTS/RIMOTS
  68. GRB 020321: Candidate X-ray Counterparts
  69. GRB020406(?), optical observations
  70. GRB 020331, NIR observations
  71. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  72. GRB 020321: Optical observations
  73. GRB020317: optical observations
  74. GRB 020317 : KISO Optical Observations
  75. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  76. GRB 020317: Optical observations
  77. GRB020305: Properties of the Candidate Optical Afterglow
  78. GRB011130 (XRF011130) Second Epoch Chandra Observations
  79. GRB020305, optical observations
  80. GRB 020305: Optical observations
  81. GRB 010921: HST Observations
  82. IPN detection and localization of Cygnus X-1 flares
  83. RXTE Observations of SGR 1900+14
  84. SGR1900+14 activity
  85. IPN/HETE Detection of Bursts from SGR1900+14
  86. IPN Upper Limits to a GRB Associated With SN2002ap
  87. SN2002ap (SN/GRB?) optical spectrographic observations
  88. IPN detection of further activity from SGR1806-20
  89. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  90. IPN observations of SGR1806-20
  91. GRB 020124: Optical afterglow
  92. Possible optical counterpart to a GRB
  93. GRB011212, Optical Observations
  94. GRB011212: Optical observations at Gunma
  95. GRB011212: Optical observations
  96. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  97. GRB001109, Radio Monitoring
  98. GRB011121: fainter still
  99. GRB011121: fading behavior
  100. GRB 011030: TNG K-band observation

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