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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"

42595 results found.

  1. GRB040827 XMM-Newton observation
  2. GRB040825A: optical limit before GRB
  3. GRB 040825B: Optical observations
  4. GRB040827 optical observations
  5. GRB 040827 - Refined position
  6. GRB 040827 - A long GRB detected by INTEGRAL
  7. GRB040825B, BVRcIc field photometry
  8. GRB040825A, BVRcIc field photometry
  9. Increase of SGR 1806-20 activity
  10. GRB040825A: optical observations
  11. GRB040825B: optical observations
  12. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  13. GRB 040825A: Optical observations.
  14. GRB 040825: Optical observations
  15. XRF040812: possible afterglow second Chandra observation
  16. GRB 040812: Second epoch CXO Observations
  17. GRB040823,optical observation
  18. XRF040812: GMRT observations
  19. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  20. XRF 040812: optical observation at VLT
  21. GRB 040812: Optical counterparts of CXO sources
  22. XRF040812: possible afterglow
  23. CXO observation of GRB 040812
  24. Bursting activity from SGR 1806-20 detected with IBAS
  25. IPN/HETE localizations of GRB040810 (=H3489)
  26. GRB 040812: Keck and LCO optical observations
  27. GRB 040812: Keck and LCO observations
  28. GRB 040812: radio observations
  29. GRB040812, optical/IR observations
  30. Konus-Wind observation of GRB040810 (=H3489)
  31. GRB 040812: a long GRB detected by INTEGRAL
  32. GRB 040810: Optical observations of a limited region
  33. XRF040701: Optical Observations at ESO
  34. IPN/HETE triangulation of GRB040802 (=H3485)
  35. GRB 040730, infrared observations
  36. GRB 040730: Optical observations
  37. GRB 040730: a long GRB detected with INTEGRAL
  38. Ongoing activity of SGR 1806-20
  39. GRB040624: optical monitoring at TNG
  40. XRF 040701 - optical observations of the decaying Chandra source
  41. XRF040701: Second-Epoch Chandra Observations
  42. XRF040701: VLA Observations
  43. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  44. XRF040701: First-Epoch Chandra Observations
  45. IBAS Alert 1836: NOT a real GRB
  46. GRB040709 J,H-band observations
  47. GRB040624, optical observations
  48. XRF 040701, optical observations
  49. XRF040701 (=U11548): a bright XRF detected by HETE
  50. GRB 040624: optical observations
  51. Optical Observations of GRB040624
  52. GRB 040624: optical observations at TNG and VLT
  53. GRB 040624: R-band observations
  54. GRB 040624, optical observations
  55. GRB 040624 - A long GRB detected with INTEGRAL
  56. GRB 030329: Rebrightening of hyperluminal ejecta.
  57. IPN Summary of SGR1806-20 Activity in 2004
  58. GRB040511: Retraction of redshift identification
  59. SGR 1806-20: no IR variability of the proposed counterparts
  60. SGR 1806-20, potential NIR counterpart
  61. GRB 040606: Optical observations
  62. Activivty of SGR 1806-20
  63. IPN triangulation of an intense intermediate burst from SGR1806-20
  64. GRB 040511, very fast decay?
  65. GRB 030324: Detection and Color of Host Galaxy
  66. GRB 040511: NIR observations with REM
  67. GRB040511: Redshift identifcation
  68. GRB 040511: Optical limit
  69. GRB040511: Candidate optical/NIR afterglow
  70. IBAS GRB Alerts n.1785 to 1791
  71. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  72. GRB 040511: Second Epoch Optical Observations
  73. IBAS GRB Alerts 1781-4
  74. GRB 040511: Optical observations
  75. GRB 040511: Optical Observations
  76. GRB040511: Optical Observations
  77. GRB040511: Optical Observations
  78. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  79. IBAS GRB Alert number 1774: NOT a real GRB
  80. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  81. IBAS Alerts 1771 and 1772: NOT a real GRB
  82. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  83. IPN triangulation of GRB040425 (=H3183)
  84. On Line Availability of Archival HETE Fregate Data and Lightcurves
  85. GRB 040423 (=H3175): A Long GRB Localized by HETE
  86. GRB040422, optical observations at Loiano
  87. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  88. GRB040422, BVRcIc field calibration
  89. GRB 040422,optical observation
  90. GRB040422: optical and NIR observations at the VLT
  91. GRB 040422: a long GRB detected with INTEGRAL
  92. GRB 040403, deep optical observations
  93. INTEGRAL-SPI/ACS GRB data: timing correction
  94. IBAS GRB alerts 1739, 1740, 1741
  95. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  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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