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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. XRF040701: First-Epoch Chandra Observations
  2. IBAS Alert 1836: NOT a real GRB
  3. GRB040709 J,H-band observations
  4. GRB040624, optical observations
  5. GRB040706:observation at University of Miyazaki
  6. XRF 040701, optical observations
  7. XRF040701 (=U11548): a bright XRF detected by HETE
  8. GRB 040624: optical observations
  9. Optical Observations of GRB040624
  10. GRB 040624: optical observations at TNG and VLT
  11. MASTER: GRB 040624 optical observation after 0,48d
  12. GRB 040624: R-band observations
  13. GRB 040624, optical observations
  14. GRB 040624 - A long GRB detected with INTEGRAL
  15. GRB 030329: Rebrightening of hyperluminal ejecta.
  16. IPN Summary of SGR1806-20 Activity in 2004
  17. GRB040511: Retraction of redshift identification
  18. SGR 1806-20: no IR variability of the proposed counterparts
  19. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  20. SGR 1806-20, potential NIR counterpart
  21. GRB 040606: Optical observations
  22. MASTER: HETE Alert 3274 optical observation
  23. Activivty of SGR 1806-20
  24. IPN triangulation of an intense intermediate burst from SGR1806-20
  25. GRB 040511, very fast decay?
  26. GRB 030324: Detection and Color of Host Galaxy
  27. GRB 040511: NIR observations with REM
  28. GRB040511: Redshift identifcation
  29. GRB 040511: Optical limit
  30. GRB040511: Candidate optical/NIR afterglow
  31. IBAS GRB Alerts n.1785 to 1791
  32. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  33. GRB 040511: Second Epoch Optical Observations
  34. IBAS GRB Alerts 1781-4
  35. GRB 040511: Optical observations
  36. GRB 040511: Optical Observations
  37. GRB040511: Optical Observations
  38. GRB040511: Optical Observations
  39. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  40. IBAS GRB Alert number 1774: NOT a real GRB
  41. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  42. IBAS Alerts 1771 and 1772: NOT a real GRB
  43. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  44. IPN triangulation of GRB040425 (=H3183)
  45. On Line Availability of Archival HETE Fregate Data and Lightcurves
  46. GRB040422: optical observations at Xinglong Observatory
  47. GRB040422: optical observations at CrAO
  48. GRB 040423 (=H3175): A Long GRB Localized by HETE
  49. GRB040422, optical observations at Loiano
  50. GRB040422 : I-band follow-up observation at Lulin Observatory
  51. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  52. GRB040422, BVRcIc field calibration
  53. GRB 040422,optical observation
  54. GRB040422: optical and NIR observations at the VLT
  55. GRB 040422: a long GRB detected with INTEGRAL
  56. GRB 040403, deep optical observations
  57. MASTER: HETE Alert 3163, 3167 technical optical observation
  58. INTEGRAL-SPI/ACS GRB data: timing correction
  59. IBAS GRB alerts 1739, 1740, 1741
  60. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  61. GRB 040403: Optical Observations
  62. GRB 040403 Optical Observations
  63. GRB 040403: Optical observations
  64. GRB 040403: optical observations
  65. GRB 040403: Optical Observations
  66. GRB 040403: a long GRB detected with INTEGRAL
  67. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  68. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  69. IBAS GRB Alert 1694
  70. GRB040323: NIR Observations and Variable Object
  71. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  72. GRB 040323, a dark GRB ?
  73. short hard GRB 040322
  74. GRB 040323: a long GRB detected with INTEGRAL
  75. IBAS GRB alerts 1679, 1680, 1681
  76. GRB040223: Deep NIR NTT data re-analysis
  77. GRB 040223: XMM-Newton results
  78. GRB040223, improved XMM position
  79. IBAS Alert 1678: not a GRB
  80. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  81. GRB 031203, possible supernova
  82. MASTER: RXTE GRB040308 optical observation
  83. IBAS results on a burst from SGR1806-20
  84. INTEGRAL detection of activity from SGR1806-20
  85. RXTE GRB040229 optical observation: no candidate
  86. GRB 040228 Optical observations
  87. IPN triangulation of GRB040228 (H3066, H3067)
  88. GRB040228 : KISO optical follow-up observation
  89. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  90. GRB 040223: Deep NIR NTT observations
  91. GRB 040223 : Optical observation (non-detection)
  92. XMM-Newton Images of GRB 040223
  93. GRB 040223, VLA observations
  94. GRB 040223: REM IJK Observations
  95. GRB 040223 XMM-Newton observation ...
  96. GRB 031203 XMM-Newton observation
  97. GRB 040223 : Planned XMM-Newton observation
  98. GRB 040106 : Planned XMM-Newton observation
  99. GRB 040223: further offline analysis
  100. GRB 040223: a long GRB detected with INTEGRAL

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