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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"

19549 results found.

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

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