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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"

18338 results found.

  1. XRF 040912, identification of CXO sources
  2. XRF040912, BVRcIc field calibration
  3. XRF040916, BVRcIc field calibration
  4. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  5. GRB040916: Optical observations
  6. GRB 040912: Optical Observations
  7. GRB/XRF040912,optical observations
  8. GRB 040912, BVRI observations
  9. Optical observations of field of GRB040912
  10. HETE 3557: Optical observations
  11. GRB040827: analysis of the XMM-Newton observation
  12. GRB040903, REM near-IR observation
  13. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  14. GRB 040827 - Radio Observations
  15. XMM-Newton Images of GRB 040827
  16. GRB 040827: optical and NIR observations at the VLT
  17. GRB040827 XMM-Newton observation
  18. GRB040825A: optical limit before GRB
  19. GRB 040825B: Optical observations
  20. GRB 040827 : Planned XMM-Newton observation
  21. GRB040825B, BVRcIc field photometry
  22. GRB040825A, BVRcIc field photometry
  23. GCN GRB OBSERBATION REPORT
  24. GRB 040825A,optical observations
  25. GRB040825A: optical observations
  26. GRB040825B: optical observations
  27. GRB 040812: Second epoch CXO Observations
  28. GRB040823,optical observation
  29. XRF040812: GMRT observations
  30. XRF 040812: optical observation at VLT
  31. CXO observation of GRB 040812
  32. GRB040812, optical/IR observations
  33. XRF040701: Optical Observations at ESO
  34. GRB 040730, infrared observations
  35. GRB040624: optical monitoring at TNG
  36. XRF 040701 - optical observations of the decaying Chandra source
  37. XRF040701: Second-Epoch Chandra Observations
  38. XRF040701: First-Epoch Chandra Observations
  39. GRB040624, optical observations
  40. GRB040706:observation at University of Miyazaki
  41. Optical Observations of GRB040624
  42. GRB 040624: optical observations at TNG and VLT
  43. MASTER: GRB 040624 optical observation after 0,48d
  44. GRB 040624, optical observations
  45. IPN Summary of SGR1806-20 Activity in 2004
  46. SGR 1806-20: no IR variability of the proposed counterparts
  47. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  48. GRB 040606: Optical observations
  49. MASTER: HETE Alert 3274 optical observation
  50. GRB 040511, very fast decay?
  51. GRB 030324: Detection and Color of Host Galaxy
  52. GRB 040511: NIR observations with REM
  53. GRB040511: Candidate optical/NIR afterglow
  54. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  55. GRB 040511: Second Epoch Optical Observations
  56. GRB 040511: Optical observations
  57. GRB 040511: Optical Observations
  58. GRB040511: Optical Observations
  59. GRB040511: Optical Observations
  60. GRB 040423 (=H3175): A Long GRB Localized by HETE
  61. GRB040422 : I-band follow-up observation at Lulin Observatory
  62. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  63. GRB040422, BVRcIc field calibration
  64. GRB 040422,optical observation
  65. GRB 040403, deep optical observations
  66. MASTER: HETE Alert 3163, 3167 technical optical observation
  67. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  68. GRB 040403: Optical observations
  69. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  70. GRB040323: NIR Observations and Variable Object
  71. GRB 040323, a dark GRB ?
  72. GRB040223, improved XMM position
  73. GRB 031203, possible supernova
  74. MASTER: RXTE GRB040308 optical observation
  75. IBAS results on a burst from SGR1806-20
  76. GRB040228 : KISO optical follow-up observation
  77. GRB 040223: Deep NIR NTT observations
  78. GRB 040223 : Optical observation (non-detection)
  79. XMM-Newton Images of GRB 040223
  80. GRB 040223, VLA observations
  81. GRB 040223: REM IJK Observations
  82. GRB 040223 XMM-Newton observation ...
  83. GRB 031203 XMM-Newton observation
  84. GRB031111, optical observations
  85. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  86. GRB040106: refined X-ray transient position
  87. GRB 031220: Optical observations of Chandra X-ray sources
  88. XMM-Newton Images of GRB 040106
  89. GRB031220: observation at Univercity of Miyazaki
  90. XMM-Newton observation of GRB040106
  91. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  92. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  93. GRB 031220 : Kyoto Optical Observation
  94. GRB 031220: Subaru observation
  95. GRB 031220: Optical observation at Tokyo Tech
  96. GRB 2974 follow-up observations
  97. GRB031203, improved XMM position
  98. XMM-Newton Observations of GRB031203: Preliminary Images
  99. IPN/HETE localization of GRB031203B (=H2949; large error box)
  100. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient

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