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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"

26042 results found.

  1. Color indices of the afterglow of GRB011211
  2. GRB011212: Optical observations at Gunma
  3. GRB 011211, spectrum and optical photometry
  4. GRB 011211: Evidence for an Optical Break
  5. optical follow-up of GRB(XRF) 011211
  6. GRB 011212: optical observation at Oslo (relayed)
  7. GRB 011211, Optical Observations
  8. GRB011212: Optical observations
  9. GRB 011211: BVRi-band photometry
  10. GRB 011211 Optical Observations: Likely Afterglow
  11. GRB 011130: Magellan spectroscopy
  12. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  13. GRB011130, optical observations
  14. GRB011130, optical observations
  15. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  16. GRB001109, Radio Monitoring
  17. GRB 011121
  18. GRB 011121: J-band observations
  19. GRB 011121: NIR observations, host galaxy?
  20. GRB010921 - Milagro GeV/TeV Observations
  21. GRB 011121: HST Scheduled
  22. GRB011121: fainter still
  23. GRB 011121: Radio Observations
  24. GRB011121: continued decay
  25. GRB 011121: Detection of Bright IR Counterpart
  26. GRB011121: possible redshift, continued decay
  27. GRB011121: fading behavior
  28. GRB011121: possible optical counterpart
  29. The X-ray Flash 011030 ('GRB 011030')
  30. The Radio Afterglow from the X-ray Rich GRB 011030
  31. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  32. GRB010921, optical observation
  33. GRB 011030 I-band Observations
  34. GRB 011030 K-band Observations
  35. GRB 010921: Possible supernova component
  36. GRB010921, optical observation at early time
  37. GRB010921: Spectroscopy of the Host Galaxy
  38. GRB 010921: The afterglow of HETE #1761
  39. GRB010921, negative optical observations
  40. GRB010921 field photometry
  41. GRB 010222 - WHT BVRI images
  42. GRB 010629 Optical Observations
  43. GRB 010222 /corrections to VBT data
  44. GRB010412, field photometry
  45. GRB 980326: Late-time HST/STIS observations
  46. Further Optical Observations of GRB 010324
  47. GRB010222, late-time optical observation
  48. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  49. GRB010222: Chandra X-ray Observatory Observation
  50. GRB 010222, Optical Observations
  51. GRB 010214, I-band data
  52. Sub-millimeter Excess/GRB 010222
  53. GRB 010222 HST/Chandra TOO
  54. GRB010222: R-band data
  55. GRB010222, possible increase of optical decay slope
  56. GRB010222: fading behavior
  57. GRB 010220: Near-IR Observations
  58. GRB010214 follow-up from Hanle
  59. GRB010222: Another absorption line system
  60. GRB010222: Optical decay slope
  61. GRB010222: R-band fading behavior
  62. GRB010222: possible optical counterpart
  63. GRB010214, candidate optical afterglow
  64. GRB 010214: X-Ray afterglow
  65. GRB010213, Radio Observations
  66. J-Band Observation of GRB 010214.
  67. GRB010214 Optical Observation
  68. GRB010214: BeppoSAX/NFI Observations
  69. GRB 010214, optical observations
  70. Optical observations of GRB 001018 with JCAM
  71. GRB 001212 Optical Observation
  72. GRB001120: Gunn-i observations
  73. Optical/NIR observations of GRB001109
  74. GRB 001109: deep JHK upper limits
  75. GRB 001109 X-ray afterglow with BeppoSAX
  76. GRB001007: Optical observations
  77. GRB001007, Radio observations
  78. GRB 001018, Possible Radio Afterglow
  79. GRB 000926: Improved Absorber Redshift
  80. The Likely Optical/Infrared Afterglow of GRB 001011
  81. HETE positions added to GCN
  82. GRB001007: Optical observations
  83. GRB 000926 Chandra Observation
  84. Public availability of BeppoSAX data of GRB000926
  85. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  86. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  87. GRB000926 : increasing optical decay slope
  88. GRB 000926: Lightcurve Update and Predictions
  89. GRB 000926, optical observation by Oksanen (vsnet-grb)
  90. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  91. GRB 000926: Preliminary R-band Lightcurve
  92. GRB 000926 HST/Chandra TOO Status
  93. Spectroscopic Redshift of GRB 000926
  94. GRB000911: Optical observations
  95. GRB000830, BVRI field photometry
  96. GRB000830: Optical observations
  97. "Snapshot" afterglow IDs and GRB 000830
  98. GRB000830: Optical observations
  99. HST/STIS observations of the chaotic environment of GRB 980613
  100. GRB000812, Radio observations

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