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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"

20363 results found.

  1. GRB 040827: Possible detection of optical afterglow
  2. GRB040827 XMM-Newton observation
  3. GRB040825A: optical limit before GRB
  4. GRB 040825B: Optical observations
  5. GRB 040827 : Planned XMM-Newton observation
  6. GRB040825B, BVRcIc field photometry
  7. GRB040825A, BVRcIc field photometry
  8. GCN GRB OBSERBATION REPORT
  9. GRB 040825A,optical observations
  10. GRB040825A: optical observations
  11. GRB040825B: optical observations
  12. MASTER: GRB040825b optical observation
  13. GRB 040812: Second epoch CXO Observations
  14. GRB040823,optical observation
  15. XRF040812: GMRT observations
  16. XRF 040812: optical observation at VLT
  17. GRB 040812: Optical counterparts of CXO sources
  18. CXO observation of GRB 040812
  19. IPN/HETE localizations of GRB040810 (=H3489)
  20. GRB040812, optical/IR observations
  21. Konus-Wind observation of GRB040810 (=H3489)
  22. GRB 040810: Optical observations of a limited region
  23. XRF040701: Optical Observations at ESO
  24. GRB 040730, infrared observations
  25. GRB040624: optical monitoring at TNG
  26. XRF 040701 - optical observations of the decaying Chandra source
  27. XRF040701: Second-Epoch Chandra Observations
  28. XRF040701: VLA Observations
  29. XRF040701: First-Epoch Chandra Observations
  30. GRB040624, optical observations
  31. GRB040706:observation at University of Miyazaki
  32. Optical Observations of GRB040624
  33. GRB 040624: optical observations at TNG and VLT
  34. MASTER: GRB 040624 optical observation after 0,48d
  35. GRB 040624, optical observations
  36. GRB 030329: Rebrightening of hyperluminal ejecta.
  37. IPN Summary of SGR1806-20 Activity in 2004
  38. SGR 1806-20: no IR variability of the proposed counterparts
  39. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  40. GRB 040606: Optical observations
  41. MASTER: HETE Alert 3274 optical observation
  42. Activivty of SGR 1806-20
  43. GRB 040511, very fast decay?
  44. GRB 030324: Detection and Color of Host Galaxy
  45. GRB 040511: NIR observations with REM
  46. GRB040511: Candidate optical/NIR afterglow
  47. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  48. GRB 040511: Second Epoch Optical Observations
  49. IBAS GRB Alerts 1781-4
  50. GRB 040511: Optical observations
  51. GRB 040511: Optical Observations
  52. GRB040511: Optical Observations
  53. GRB040511: Optical Observations
  54. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  55. GRB 040423 (=H3175): A Long GRB Localized by HETE
  56. GRB040422 : I-band follow-up observation at Lulin Observatory
  57. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  58. GRB040422, BVRcIc field calibration
  59. GRB 040422,optical observation
  60. GRB 040403, deep optical observations
  61. MASTER: HETE Alert 3163, 3167 technical optical observation
  62. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  63. GRB 040403: Optical observations
  64. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  65. GRB040323: NIR Observations and Variable Object
  66. GRB 040323, a dark GRB ?
  67. GRB040223, improved XMM position
  68. GRB 031203, possible supernova
  69. MASTER: RXTE GRB040308 optical observation
  70. IBAS results on a burst from SGR1806-20
  71. GRB040228 : KISO optical follow-up observation
  72. GRB 040223: Deep NIR NTT observations
  73. GRB 040223 : Optical observation (non-detection)
  74. XMM-Newton Images of GRB 040223
  75. GRB 040223, VLA observations
  76. GRB 040223: REM IJK Observations
  77. GRB 040223 XMM-Newton observation ...
  78. GRB 031203 XMM-Newton observation
  79. GRB031111, optical observations
  80. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  81. GRB040106, follow-up radio observations
  82. GRB040106: refined X-ray transient position
  83. GRB 031220: Optical observations of Chandra X-ray sources
  84. XMM-Newton Images of GRB 040106
  85. GRB031220: observation at Univercity of Miyazaki
  86. XMM-Newton observation of GRB040106
  87. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  88. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  89. GRB 031220 : Kyoto Optical Observation
  90. GRB 031220: Subaru observation
  91. GRB 031220: Optical observation at Tokyo Tech
  92. GRB 2974 follow-up observations
  93. GRB031203, improved XMM position
  94. GRB 021203: A Normal GRB viewed far off axis?
  95. XMM-Newton Observations of GRB031203: Preliminary Images
  96. GRB 031203: Optical/IR Astrometry
  97. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  98. XMM-Newton Observation of GRB031203
  99. GRB 031203: Deep NIR NTT & VLT observations
  100. XMM-Newton Observation of GRB031203

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