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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"

26040 results found.

  1. GRB 011211, spectrum and optical photometry
  2. GRB 011211: Evidence for an Optical Break
  3. optical follow-up of GRB(XRF) 011211
  4. GRB 011212: optical observation at Oslo (relayed)
  5. GRB 011211, Optical Observations
  6. GRB011212: Optical observations
  7. GRB 011211: BVRi-band photometry
  8. GRB 011211 Optical Observations: Likely Afterglow
  9. GRB 011130: Magellan spectroscopy
  10. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  11. GRB011130, optical observations
  12. GRB011130, optical observations
  13. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  14. GRB001109, Radio Monitoring
  15. GRB 011121
  16. GRB 011121: J-band observations
  17. GRB 011121: NIR observations, host galaxy?
  18. GRB010921 - Milagro GeV/TeV Observations
  19. GRB 011121: HST Scheduled
  20. GRB011121: fainter still
  21. GRB 011121: Radio Observations
  22. GRB011121: continued decay
  23. GRB 011121: Detection of Bright IR Counterpart
  24. GRB011121: possible redshift, continued decay
  25. GRB011121: fading behavior
  26. GRB011121: possible optical counterpart
  27. The X-ray Flash 011030 ('GRB 011030')
  28. The Radio Afterglow from the X-ray Rich GRB 011030
  29. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  30. GRB010921, optical observation
  31. GRB 011030 I-band Observations
  32. GRB 011030 K-band Observations
  33. GRB 010921: Possible supernova component
  34. GRB010921, optical observation at early time
  35. GRB010921: Spectroscopy of the Host Galaxy
  36. GRB 010921: The afterglow of HETE #1761
  37. GRB010921, negative optical observations
  38. GRB010921 field photometry
  39. GRB 010222 - WHT BVRI images
  40. GRB 010629 Optical Observations
  41. GRB 010222 /corrections to VBT data
  42. GRB010412, field photometry
  43. GRB 980326: Late-time HST/STIS observations
  44. Further Optical Observations of GRB 010324
  45. GRB010222, late-time optical observation
  46. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  47. GRB010222: Chandra X-ray Observatory Observation
  48. GRB 010222, Optical Observations
  49. GRB 010214, I-band data
  50. Sub-millimeter Excess/GRB 010222
  51. GRB 010222 HST/Chandra TOO
  52. GRB010222: R-band data
  53. GRB010222, possible increase of optical decay slope
  54. GRB010222: fading behavior
  55. GRB 010220: Near-IR Observations
  56. GRB010214 follow-up from Hanle
  57. GRB010222: Another absorption line system
  58. GRB010222: Optical decay slope
  59. GRB010222: R-band fading behavior
  60. GRB010222: possible optical counterpart
  61. GRB010214, candidate optical afterglow
  62. GRB 010214: X-Ray afterglow
  63. GRB010213, Radio Observations
  64. J-Band Observation of GRB 010214.
  65. GRB010214 Optical Observation
  66. GRB010214: BeppoSAX/NFI Observations
  67. GRB 010214, optical observations
  68. Optical observations of GRB 001018 with JCAM
  69. GRB 001212 Optical Observation
  70. GRB001120: Gunn-i observations
  71. Optical/NIR observations of GRB001109
  72. GRB 001109: deep JHK upper limits
  73. GRB 001109 X-ray afterglow with BeppoSAX
  74. GRB001007: Optical observations
  75. GRB001007, Radio observations
  76. GRB 001018, Possible Radio Afterglow
  77. GRB 000926: Improved Absorber Redshift
  78. The Likely Optical/Infrared Afterglow of GRB 001011
  79. HETE positions added to GCN
  80. GRB001007: Optical observations
  81. GRB 000926 Chandra Observation
  82. Public availability of BeppoSAX data of GRB000926
  83. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  84. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  85. GRB000926 : increasing optical decay slope
  86. GRB 000926: Lightcurve Update and Predictions
  87. GRB 000926, optical observation by Oksanen (vsnet-grb)
  88. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  89. GRB 000926: Preliminary R-band Lightcurve
  90. GRB 000926 HST/Chandra TOO Status
  91. Spectroscopic Redshift of GRB 000926
  92. GRB000911: Optical observations
  93. GRB000830, BVRI field photometry
  94. GRB000830: Optical observations
  95. "Snapshot" afterglow IDs and GRB 000830
  96. GRB000830: Optical observations
  97. HST/STIS observations of the chaotic environment of GRB 980613
  98. GRB000812, Radio observations
  99. GRB 991208 Host Galaxy Imaging
  100. GRB 991216, HST/STIS observations

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