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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"
  1. GRB040422: optical observations at CrAO
  2. GRB 040423 (=H3175): A Long GRB Localized by HETE
  3. GRB040422, optical observations at Loiano
  4. GRB040422 : I-band follow-up observation at Lulin Observatory
  5. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  6. GRB040422, BVRcIc field calibration
  7. GRB 040422,optical observation
  8. GRB040422: optical and NIR observations at the VLT
  9. GRB 040422: a long GRB detected with INTEGRAL
  10. GRB 040403, deep optical observations
  11. MASTER: HETE Alert 3163, 3167 technical optical observation
  12. INTEGRAL-SPI/ACS GRB data: timing correction
  13. IBAS GRB alerts 1739, 1740, 1741
  14. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  15. GRB 040403: Optical Observations
  16. GRB 040403 Optical Observations
  17. GRB 040403: Optical observations
  18. GRB 040403: optical observations
  19. GRB 040403: Optical Observations
  20. GRB 040403: a long GRB detected with INTEGRAL
  21. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  22. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  23. IBAS GRB Alert 1694
  24. GRB040323: NIR Observations and Variable Object
  25. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  26. GRB 040323, a dark GRB ?
  27. short hard GRB 040322
  28. GRB 040323: a long GRB detected with INTEGRAL
  29. IBAS GRB alerts 1679, 1680, 1681
  30. GRB040223: Deep NIR NTT data re-analysis
  31. GRB 040223: XMM-Newton results
  32. GRB040223, improved XMM position
  33. IBAS Alert 1678: not a GRB
  34. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  35. GRB 031203, possible supernova
  36. MASTER: RXTE GRB040308 optical observation
  37. IBAS results on a burst from SGR1806-20
  38. INTEGRAL detection of activity from SGR1806-20
  39. RXTE GRB040229 optical observation: no candidate
  40. GRB 040228 Optical observations
  41. IPN triangulation of GRB040228 (H3066, H3067)
  42. GRB040228 : KISO optical follow-up observation
  43. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  44. GRB 040223: Deep NIR NTT observations
  45. GRB 040223 : Optical observation (non-detection)
  46. XMM-Newton Images of GRB 040223
  47. GRB 040223, VLA observations
  48. GRB 040223: REM IJK Observations
  49. GRB 040223 XMM-Newton observation ...
  50. GRB 031203 XMM-Newton observation
  51. GRB 040223 : Planned XMM-Newton observation
  52. GRB 040106 : Planned XMM-Newton observation
  53. GRB 040223: further offline analysis
  54. GRB 040223: a long GRB detected with INTEGRAL
  55. GRB031111, optical observations
  56. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  57. GRB031203: Chandra Observations
  58. GRB040106, follow-up radio observations
  59. GRB040106: refined X-ray transient position
  60. Follow-up on IBAS GRB Alert 1379
  61. IBAS GRB alert 1379
  62. SN 2003dh/GRB030329 late-time optical spectroscopy
  63. GRB040106, Radio Observations
  64. GRB040106, likely optical afterglow
  65. GRB040106: Second Epoch Optical Observations
  66. GRB 031220: Optical observations of Chandra X-ray sources
  67. XMM-Newton Images of GRB 040106
  68. GRB040106: optical observations with REM+ROSS
  69. GRB031220: observation at Univercity of Miyazaki
  70. GRB 040106: Optical observations
  71. XMM-Newton observation of GRB040106
  72. GRB 040106 : Planned XMM-Newton observation
  73. GRB 040106 : peak flux
  74. GRB 040106 : a long GRB detected with INTEGRAL
  75. IPN triangulation of an intermediate burst from SGR1806-20
  76. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  77. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  78. GRB031225a triangulation (annulus)
  79. IPN triangulation of GRB031219 (large error box)
  80. GRB031220: Palomar Observations
  81. GRB 031220 : Kyoto Optical Observation
  82. GRB 031220: Subaru observation
  83. GRB 031220: Optical observation at Tokyo Tech
  84. GRB031220: ROTSE-IIIb Optical Limits
  85. GRB031220 : Optical Observation of Lulin Observatory
  86. GRB 031203 I-band monitoring
  87. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  88. GRB 2974 follow-up observations
  89. GRB031203, improved XMM position
  90. GRB 031203: Discovery of a dust echo
  91. GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
  92. GRB030921 triangulation (annulus)
  93. GRB 031203: SMARTS optical monitoring
  94. GRB 021203: A Normal GRB viewed far off axis?
  95. XMM-Newton Observations of GRB031203: Preliminary Images
  96. GRB 031203: Variable Radio Source
  97. GRB 031203: Magellan spectrum of possible GRB host
  98. GRB 031203: Optical/IR Astrometry
  99. IPN/HETE localization of GRB031203B (=H2949; large error box)
  100. GRB031203 K prime photometry: correction to galaxy coordinates

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