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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"

16167 results found.

  1. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  2. XRF040916: continuing decay of OT
  3. GRB040912(=H3557): Candidate Optical Afterglow
  4. XRF040916, optical observations
  5. XRF040916: Optical Transient Candidate by Subaru
  6. GRB040916 optical limits 17 min after GRB
  7. XRF 040912, identification of CXO sources
  8. XRF 040912 (=H3557): Spectral and Temporal Properties
  9. XRF040916: optical follow-up observations
  10. GRB040916: Archival optical observations
  11. XRF 040916, optical follow-up
  12. GRB040916: Optical observations
  13. GRB040916 (= H3558): Improved Localization from HETE WXM
  14. GRB040916 (= H3558): A Long XRF Localized by HETE
  15. GRB040912 (= H3557): Chandra Observations Scheduled
  16. GRB 040912: Optical Observations
  17. GRB/XRF040912,optical observations
  18. Optical observations of GRB/XRF 040912 = HETE 3557
  19. GRB040912 : Kiso Optical follow-up observation
  20. Optical observations of field of GRB040912
  21. HETE 3557: Optical observations
  22. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  23. GRB040827: analysis of the XMM-Newton observation
  24. GRB040825A: Optical observations
  25. GRB040825A: Optical observations
  26. GRB 040827: optical and NIR observations at the VLT
  27. GRB 040827: Detection of NIR afterglow
  28. GRB 040827: Possible detection of optical afterglow
  29. GRB 040827: RTT150 optical observations
  30. GRB040825A: optical limit before GRB
  31. MASTER: GRB040827 possible OT
  32. GRB 040825B: Optical observations
  33. GRB040827 optical observations
  34. GRB 040825A,optical observations
  35. GRB040825A: optical observations
  36. GRB040825B: optical observations
  37. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  38. GRB 040825A: Optical observations.
  39. MASTER: GRB040825a optical observation
  40. MASTER: GRB040825b optical observation
  41. GRB 040825: Optical observations
  42. GRB040823,optical observation
  43. XRF 040812: optical observation at VLT
  44. GRB 040812: Optical counterparts of CXO sources
  45. CXO observation of GRB 040812
  46. GRB 040812: Keck and LCO optical observations
  47. GRB040812, optical/IR observations
  48. GRB 040810: Optical observations of a limited region
  49. XRF040701: Optical Observations at ESO
  50. GRB 040730: Optical observations
  51. GRB040624: optical monitoring at TNG
  52. XRF 040701 - optical observations of the decaying Chandra source
  53. GRB040624, optical observations
  54. XRF 040701, optical observations
  55. XRF040701 (=U11548): a bright XRF detected by HETE
  56. GRB 040624: optical observations
  57. Optical Observations of GRB040624
  58. GRB 040624: optical observations at TNG and VLT
  59. MASTER: GRB 040624 optical observation after 0,48d
  60. GRB 040624: R-band observations
  61. GRB 040624, optical observations
  62. GRB 030329: Rebrightening of hyperluminal ejecta.
  63. GRB040511: Retraction of redshift identification
  64. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  65. GRB 040606: Optical observations
  66. MASTER: HETE Alert 3274 optical observation
  67. GRB 040511: NIR observations with REM
  68. GRB 040511: Optical limit
  69. GRB040511: Candidate optical/NIR afterglow
  70. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  71. GRB 040511: Second Epoch Optical Observations
  72. GRB 040511: Optical observations
  73. GRB 040511: Optical Observations
  74. GRB040511: Optical Observations
  75. GRB040511: Optical Observations
  76. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  77. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  78. On Line Availability of Archival HETE Fregate Data and Lightcurves
  79. GRB040422: optical observations at Xinglong Observatory
  80. GRB040422: optical observations at CrAO
  81. GRB 040423 (=H3175): A Long GRB Localized by HETE
  82. GRB040422, optical observations at Loiano
  83. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  84. GRB 040422,optical observation
  85. GRB040422: optical and NIR observations at the VLT
  86. GRB 040403, deep optical observations
  87. MASTER: HETE Alert 3163, 3167 technical optical observation
  88. GRB 040403: Optical Observations
  89. GRB 040403 Optical Observations
  90. GRB 040403: Optical observations
  91. GRB 040403: optical observations
  92. GRB 040403: Optical Observations
  93. GRB040323: NIR Observations and Variable Object
  94. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  95. GRB 040323, a dark GRB ?
  96. GRB040223, improved XMM position
  97. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  98. MASTER: RXTE GRB040308 optical observation
  99. RXTE GRB040229 optical observation: no candidate
  100. GRB 040228 Optical observations

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