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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"

19548 results found.

  1. GRB041006,optical observation
  2. GRB041006: Fading of optical afterglow candidate
  3. GRB 041006: Optical afterglow candidate
  4. SGR 1806-20 still active
  5. radio observations, GRB 040924
  6. GRB040929,optical observation
  7. GRB040924,optical observation
  8. GRB040924,optical observation
  9. GRB040924: KAIT observations
  10. GRB 040924: Subaru NIR observation
  11. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  12. XRF040916: continuing decay of OT
  13. TAROT Observations of GRB 040916 (HETE #3558)
  14. GRB040912(=H3557): Candidate Optical Afterglow
  15. XRF040916, optical observations
  16. XRF 040912, identification of CXO sources
  17. XRF040912, BVRcIc field calibration
  18. XRF040916, BVRcIc field calibration
  19. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  20. GRB040916: Optical observations
  21. GRB 040912: Optical Observations
  22. GRB/XRF040912,optical observations
  23. GRB 040912, BVRI observations
  24. Optical observations of field of GRB040912
  25. HETE 3557: Optical observations
  26. GRB040827: analysis of the XMM-Newton observation
  27. GRB040903, REM near-IR observation
  28. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  29. Possible GRB 040903 - further analysis
  30. GRB 040827 - Radio Observations
  31. XMM-Newton Images of GRB 040827
  32. GRB 040827: optical and NIR observations at the VLT
  33. GRB040827 XMM-Newton observation
  34. GRB 040825B: Optical observations
  35. GRB 040827 : Planned XMM-Newton observation
  36. GRB 040827 : peak flux
  37. GRB040825B, BVRcIc field photometry
  38. GRB040825A, BVRcIc field photometry
  39. GCN GRB OBSERBATION REPORT
  40. GRB 040825A,optical observations
  41. GRB040825A: optical observations
  42. GRB040825B: optical observations
  43. GRB040823,optical observation
  44. XRF040812: GMRT observations
  45. XRF 040812: optical observation at VLT
  46. Bursting activity from SGR 1806-20 detected with IBAS
  47. GRB 040812: Keck and LCO optical observations
  48. GRB 040812: Keck and LCO observations
  49. GRB 040812: radio observations
  50. GRB040812, optical/IR observations
  51. GRB 040812: a long GRB detected by INTEGRAL
  52. XRF040701: Optical Observations at ESO
  53. IPN/HETE triangulation of GRB040802 (=H3485)
  54. GRB 040730, infrared observations
  55. GRB 040730: a long GRB detected with INTEGRAL
  56. GRB040624: optical monitoring at TNG
  57. XRF 040701 - optical observations of the decaying Chandra source
  58. XRF040701: Second-Epoch Chandra Observations
  59. XRF040701: First-Epoch Chandra Observations
  60. GRB040624, optical observations
  61. GRB040706:observation at University of Miyazaki
  62. XRF040701 (=U11548): a bright XRF detected by HETE
  63. Optical Observations of GRB040624
  64. GRB 040624: optical observations at TNG and VLT
  65. MASTER: GRB 040624 optical observation after 0,48d
  66. GRB 040624, optical observations
  67. GRB 040624 - A long GRB detected with INTEGRAL
  68. IPN Summary of SGR1806-20 Activity in 2004
  69. SGR 1806-20: no IR variability of the proposed counterparts
  70. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  71. SGR 1806-20, potential NIR counterpart
  72. GRB 040606: Optical observations
  73. MASTER: HETE Alert 3274 optical observation
  74. GRB 040511, very fast decay?
  75. GRB 030324: Detection and Color of Host Galaxy
  76. GRB 040511: NIR observations with REM
  77. GRB040511: Candidate optical/NIR afterglow
  78. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  79. GRB 040511: Second Epoch Optical Observations
  80. GRB 040511: Optical observations
  81. GRB 040511: Optical Observations
  82. GRB040511: Optical Observations
  83. GRB040511: Optical Observations
  84. GRB 040423 (=H3175): A Long GRB Localized by HETE
  85. GRB040422 : I-band follow-up observation at Lulin Observatory
  86. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  87. GRB040422, BVRcIc field calibration
  88. GRB 040422,optical observation
  89. GRB 040422: a long GRB detected with INTEGRAL
  90. GRB 040403, deep optical observations
  91. MASTER: HETE Alert 3163, 3167 technical optical observation
  92. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  93. GRB 040403: Optical observations
  94. GRB 040403: a long GRB detected with INTEGRAL
  95. GRB040323: NIR Observations and Variable Object
  96. GRB 040323, a dark GRB ?
  97. GRB040223, improved XMM position
  98. GRB 031203, possible supernova
  99. MASTER: RXTE GRB040308 optical observation
  100. IBAS results on a burst from SGR1806-20

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