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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. GRB 040825: Optical observations
  2. XRF040812: possible afterglow second Chandra observation
  3. GRB 040812: Second epoch CXO Observations
  4. GRB040823,optical observation
  5. XRF040812: GMRT observations
  6. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  7. XRF 040812: optical observation at VLT
  8. GRB 040812: Optical counterparts of CXO sources
  9. XRF040812: possible afterglow
  10. CXO observation of GRB 040812
  11. Bursting activity from SGR 1806-20 detected with IBAS
  12. IPN/HETE localizations of GRB040810 (=H3489)
  13. GRB 040812: Keck and LCO optical observations
  14. GRB 040812: Keck and LCO observations
  15. GRB 040812: radio observations
  16. GRB040812, optical/IR observations
  17. Konus-Wind observation of GRB040810 (=H3489)
  18. GRB 040812: a long GRB detected by INTEGRAL
  19. GRB 040810: Optical observations of a limited region
  20. XRF040701: Optical Observations at ESO
  21. IPN/HETE triangulation of GRB040802 (=H3485)
  22. GRB 040730, infrared observations
  23. GRB 040730: Optical observations
  24. GRB 040730: a long GRB detected with INTEGRAL
  25. Ongoing activity of SGR 1806-20
  26. GRB040624: optical monitoring at TNG
  27. XRF 040701 - optical observations of the decaying Chandra source
  28. XRF040701: Second-Epoch Chandra Observations
  29. Cancellation of IBAS/INTEGRAL GRB alerts
  30. XRF040701: VLA Observations
  31. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  32. XRF040701: First-Epoch Chandra Observations
  33. IBAS Alert 1836: NOT a real GRB
  34. GRB040709 J,H-band observations
  35. GRB040624, optical observations
  36. GRB040706:observation at University of Miyazaki
  37. XRF 040701, optical observations
  38. XRF040701 (=U11548): a bright XRF detected by HETE
  39. GRB 040624: optical observations
  40. Optical Observations of GRB040624
  41. GRB 040624: optical observations at TNG and VLT
  42. MASTER: GRB 040624 optical observation after 0,48d
  43. GRB 040624: R-band observations
  44. GRB 040624, optical observations
  45. GRB 040624 - A long GRB detected with INTEGRAL
  46. GRB 030329: Rebrightening of hyperluminal ejecta.
  47. IPN Summary of SGR1806-20 Activity in 2004
  48. GRB040511: Retraction of redshift identification
  49. SGR 1806-20: no IR variability of the proposed counterparts
  50. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  51. SGR 1806-20, potential NIR counterpart
  52. GRB 040606: Optical observations
  53. MASTER: HETE Alert 3274 optical observation
  54. Activivty of SGR 1806-20
  55. IPN triangulation of an intense intermediate burst from SGR1806-20
  56. GRB 040511, very fast decay?
  57. GRB 030324: Detection and Color of Host Galaxy
  58. GRB 040511: NIR observations with REM
  59. GRB040511: Redshift identifcation
  60. GRB 040511: Optical limit
  61. GRB040511: Candidate optical/NIR afterglow
  62. IBAS GRB Alerts n.1785 to 1791
  63. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  64. GRB 040511: Second Epoch Optical Observations
  65. IBAS GRB Alerts 1781-4
  66. GRB 040511: Optical observations
  67. GRB 040511: Optical Observations
  68. GRB040511: Optical Observations
  69. GRB040511: Optical Observations
  70. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  71. IBAS GRB Alert number 1774: NOT a real GRB
  72. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  73. IBAS Alerts 1771 and 1772: NOT a real GRB
  74. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  75. IPN triangulation of GRB040425 (=H3183)
  76. On Line Availability of Archival HETE Fregate Data and Lightcurves
  77. GRB040422: optical observations at Xinglong Observatory
  78. GRB040422: optical observations at CrAO
  79. GRB 040423 (=H3175): A Long GRB Localized by HETE
  80. GRB040422, optical observations at Loiano
  81. GRB040422 : I-band follow-up observation at Lulin Observatory
  82. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  83. GRB040422, BVRcIc field calibration
  84. GRB 040422,optical observation
  85. GRB040422: optical and NIR observations at the VLT
  86. GRB 040422: a long GRB detected with INTEGRAL
  87. GRB 040403, deep optical observations
  88. MASTER: HETE Alert 3163, 3167 technical optical observation
  89. INTEGRAL-SPI/ACS GRB data: timing correction
  90. IBAS GRB alerts 1739, 1740, 1741
  91. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  92. GRB 040403: Optical Observations
  93. GRB 040403 Optical Observations
  94. GRB 040403: Optical observations
  95. GRB 040403: optical observations
  96. GRB 040403: Optical Observations
  97. GRB 040403: a long GRB detected with INTEGRAL
  98. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  99. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  100. IBAS GRB Alert 1694

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