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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"

24893 results found.

  1. GRB000630, optical observations
  2. GRB000630: Optical observations
  3. GRB000630, Radio Observations
  4. possible optical counterpart of GRB 000630
  5. GRB 000620, optical observations
  6. GRB000418, HST/STIS Observations
  7. GRB990123: Late-time HST/STIS observations of the host
  8. GRB000620, optical observations
  9. GRB000615: H-band observations
  10. GRB990308, HST/STIS observations of the host galaxy
  11. GRB000620 - Optical observations
  12. GRB000620 Optical observations
  13. GRB000620: BeppoSAX WFC and GRBM detection
  14. GRB000607, optical observations
  15. GRB 000615: NIR further observations
  16. GRB990123, HST/STIS observations of the host galaxy
  17. GRB000616 optical observations
  18. GRB 000615, near-infrared observations
  19. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  20. GRB000615, further R-band photometry
  21. GRB 000615: NIR observations
  22. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  23. GRB000615, R-band photometry
  24. The Hosts of GRB 980703 and GRB 971214
  25. GRB 000301C: Further Late-Time HST/STIS observations
  26. GRB000528: follow-up X-ray measurements and update of IPN annulus
  27. GRB980519, HST/STIS observations of the host galaxy
  28. GRB000604 optical non-detection
  29. GRB000604 - Optical observations
  30. GRB000604, optical observations
  31. GRB000528, optical observations at ESO
  32. GRB 000604 optical observations
  33. GRB 000418: Detection of the Host Galaxy
  34. GRB000604, optical observations, comparison with DPOSS
  35. GRB000528, Radio Observations
  36. X-ray Afterglow of GRB 000529
  37. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  38. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  39. GRB 000528 - WFC measurements
  40. GRB000519, BVRI field photometry
  41. IPN triangulation of GRB000519
  42. GRB000508B, optical photometry
  43. GRB000508B, BVR field photometry
  44. Possible GRB-related phenomenon
  45. RXTE/ASM and IPN localization of GRB 000508B
  46. GRB000424, UBVRI field photometry
  47. GRB000418, UBVRI field photometry update
  48. GRB000424, optical observations
  49. GRB 000429, optical observation
  50. GRB 000429, UBVRI field photometry
  51. GRB 000418, UBVRI field photometry
  52. GRB 000418, optical observation
  53. GRB 000418, Optical Observation
  54. GRB000418, near-infrared observations
  55. Correction to IPN error box for GRB000419
  56. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  57. GRB000416 BRJK observations
  58. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  59. GRB 000408, optical observations
  60. GRB 991208, UBVRI field photometry
  61. GRB000408, lotis optical observations
  62. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  63. GRB000301C - Addendum to GCN 623
  64. GRB 000323, optical observations
  65. GRB 000326: Optical Observations
  66. GRB000326, Radio observations
  67. GRB000313, Radio observations
  68. GRB 000313 - optical transient in the BATSE error box
  69. GRB 000307, Optical Observations
  70. GRB 000307, BVRI Field Photometry
  71. GRB 000301C: A Precise Redshift Determination
  72. GRB 000301C, Optical Observation
  73. GRB 000301C: HST/STIS CCD Imaging of the field
  74. IPN error box for GRB000307
  75. GRB000301C, optical R-band observations
  76. GRB 000301C Optical Observations
  77. GRB 000301C: K' Observations
  78. GRB000301C OT candidate optical observations
  79. GRB000301C - Host galaxy not detected in R (?)
  80. Optical observations of GRB000301c
  81. GRB000301C, Radio observations
  82. GRB000301C, Radio observations
  83. GRB000301C, near-infrared observations (JHK' imaging)
  84. GRB 000301c near-IR observations
  85. GRB 000301C, UBVRI field photometry
  86. GRB 000301C: OT confirmed
  87. GRB000301c optical observations
  88. GRB000301C, optical observations
  89. GRB000301C
  90. GRB 000301C : Optical Candidate
  91. GRB000301C: RXTE/ASM and IPN localizations
  92. GRB000226 [IPN Position]
  93. HST Observations of GRB 990712
  94. GRB 000214 near-IR observations
  95. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  96. GRB000210, Radio Observations
  97. GRB 000115, BVRI field photometry
  98. GRB000214: BeppoSAX GRBM and WFC Detection
  99. Optical observations of GRB000210
  100. GRB000210 X-ray afterglow

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