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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, BVRcIc field calibration
  2. GRB 040422,optical observation
  3. GRB040422: optical and NIR observations at the VLT
  4. GRB 040422: a long GRB detected with INTEGRAL
  5. GRB 040403, deep optical observations
  6. MASTER: HETE Alert 3163, 3167 technical optical observation
  7. INTEGRAL-SPI/ACS GRB data: timing correction
  8. IBAS GRB alerts 1739, 1740, 1741
  9. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  10. GRB 040403: Optical Observations
  11. GRB 040403 Optical Observations
  12. GRB 040403: Optical observations
  13. GRB 040403: optical observations
  14. GRB 040403: Optical Observations
  15. GRB 040403: a long GRB detected with INTEGRAL
  16. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  17. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  18. IBAS GRB Alert 1694
  19. GRB040323: NIR Observations and Variable Object
  20. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  21. GRB 040323, a dark GRB ?
  22. short hard GRB 040322
  23. GRB 040323: a long GRB detected with INTEGRAL
  24. IBAS GRB alerts 1679, 1680, 1681
  25. GRB040223: Deep NIR NTT data re-analysis
  26. GRB 040223: XMM-Newton results
  27. GRB040223, improved XMM position
  28. IBAS Alert 1678: not a GRB
  29. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  30. GRB 031203, possible supernova
  31. MASTER: RXTE GRB040308 optical observation
  32. IBAS results on a burst from SGR1806-20
  33. INTEGRAL detection of activity from SGR1806-20
  34. RXTE GRB040229 optical observation: no candidate
  35. GRB 040228 Optical observations
  36. IPN triangulation of GRB040228 (H3066, H3067)
  37. GRB040228 : KISO optical follow-up observation
  38. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  39. GRB 040223: Deep NIR NTT observations
  40. GRB 040223 : Optical observation (non-detection)
  41. XMM-Newton Images of GRB 040223
  42. GRB 040223, VLA observations
  43. GRB 040223: REM IJK Observations
  44. GRB 040223 XMM-Newton observation ...
  45. GRB 031203 XMM-Newton observation
  46. GRB 040223 : Planned XMM-Newton observation
  47. GRB 040106 : Planned XMM-Newton observation
  48. GRB 040223: further offline analysis
  49. GRB 040223: a long GRB detected with INTEGRAL
  50. GRB031111, optical observations
  51. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  52. GRB031203: Chandra Observations
  53. GRB040106, follow-up radio observations
  54. GRB040106: refined X-ray transient position
  55. Follow-up on IBAS GRB Alert 1379
  56. IBAS GRB alert 1379
  57. SN 2003dh/GRB030329 late-time optical spectroscopy
  58. GRB040106, Radio Observations
  59. GRB040106, likely optical afterglow
  60. GRB040106: Second Epoch Optical Observations
  61. GRB 031220: Optical observations of Chandra X-ray sources
  62. XMM-Newton Images of GRB 040106
  63. GRB040106: optical observations with REM+ROSS
  64. GRB031220: observation at Univercity of Miyazaki
  65. GRB 040106: Optical observations
  66. XMM-Newton observation of GRB040106
  67. GRB 040106 : Planned XMM-Newton observation
  68. GRB 040106 : peak flux
  69. GRB 040106 : a long GRB detected with INTEGRAL
  70. IPN triangulation of an intermediate burst from SGR1806-20
  71. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  72. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  73. GRB031225a triangulation (annulus)
  74. IPN triangulation of GRB031219 (large error box)
  75. GRB031220: Palomar Observations
  76. GRB 031220 : Kyoto Optical Observation
  77. GRB 031220: Subaru observation
  78. GRB 031220: Optical observation at Tokyo Tech
  79. GRB031220: ROTSE-IIIb Optical Limits
  80. GRB031220 : Optical Observation of Lulin Observatory
  81. GRB 031203 I-band monitoring
  82. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  83. GRB 2974 follow-up observations
  84. GRB031203, improved XMM position
  85. GRB 031203: Discovery of a dust echo
  86. GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
  87. GRB030921 triangulation (annulus)
  88. GRB 031203: SMARTS optical monitoring
  89. GRB 021203: A Normal GRB viewed far off axis?
  90. XMM-Newton Observations of GRB031203: Preliminary Images
  91. GRB 031203: Variable Radio Source
  92. GRB 031203: Magellan spectrum of possible GRB host
  93. GRB 031203: Optical/IR Astrometry
  94. IPN/HETE localization of GRB031203B (=H2949; large error box)
  95. GRB031203 K prime photometry: correction to galaxy coordinates
  96. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  97. XMM-Newton Observation of GRB031203
  98. GRB 031203: Deep NIR NTT & VLT observations
  99. GRB031203: K' Photometry of the likely GRB host
  100. XMM-Newton Observation of GRB031203

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