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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"

15245 results found.

  1. SGR 1900+14: Correction to GCN 1049
  2. Millimeter observation of SGR 1900+14
  3. Chandra Observations of SGR 1900+14
  4. Possible precursor to the SGR1900+14 giant burst
  5. IPN Triangulation of the Giant Flare from SGR1900+14
  6. GRB010412: Optical observations
  7. GRB010412: BeppoSAX GRBM and WFC observations
  8. REVISED LOCATION OF GRB010326A
  9. GRB010324, field photometry
  10. Further Optical Observations of GRB 010324
  11. GRB010326B: Localization by HETE (2nd GRB for this date)
  12. GRB010326: Refined Localization by HETE
  13. GRB010326: Localization by HETE
  14. IPN TRIANGULATION OF GRB010324
  15. Support extension to the BeppoSAX mission
  16. GRB 010222 - HEGRA GeV/TeV Observations
  17. GRB010220 optical obsercations
  18. GRB 010222: High-Resolution Keck Spectroscopy
  19. GRB 010214, I-band data
  20. Sub-millimeter Excess/GRB 010222
  21. GRB 010222
  22. GRB010222 further R-band photometry
  23. GRB 010222: Keck Spectroscopy
  24. GRB010222 further R-band photometry
  25. GRB 010220: Near-IR Observations
  26. GRB010214 follow-up from Hanle
  27. GRB 010222: Near-IR Observations
  28. GRB 010222, Decay Slope Confirmed
  29. GRB010222: Another absorption line system
  30. GRB 010214, Optical Observations
  31. GRB010222, radio observations
  32. GRB010222, optical observations
  33. GRB 010220, simultaneous optical observations
  34. GRB010220: BeppoSAX WFC and GRBM preliminary data
  35. GRB010214, optical observations
  36. GRB010214: BeppoSAX WFC and GRBM preliminary data
  37. GRB 010214: X-Ray afterglow
  38. GRB 010214, Optical Observations
  39. GRB 010214 optical observation
  40. GRB010213, Radio Observations
  41. J-Band Observation of GRB 010214.
  42. GRB010213 detected by HETE
  43. HETE Status
  44. IPN/RXTE TRIANGULATION OF GRB010126
  45. GRB010126: CONCAM crude optical limits during GRB
  46. GRB010126, TNG R-band observations
  47. GRB010126 Optical Observations
  48. GRB010126 optical observations
  49. IPN/RXTE TRIANGULATION OF GRB010126
  50. GRB 010119, optical observations
  51. Optical Observations of GRB 001018 at Keck
  52. Optical observations of GRB 001018 with JCAM
  53. H band observation of GRB 001212
  54. GRB001120: Gunn-i observations
  55. GRB001120, optical observations
  56. WSRT 4.8 GHz observations of GRB001109
  57. Optical/NIR observations of GRB001109
  58. GRB 001109: deep JHK upper limits
  59. GRB 001109 X-ray afterglow with BeppoSAX
  60. GRB001109, R-band optical observations
  61. GRB 991208: HST Imaging of the Host Galaxy
  62. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  63. ASM Localization of GRB 001025
  64. GRB 000926: Improved Absorber Redshift
  65. GRB 001007, BVR-band observations
  66. GRB000926 - Amateur Optical Observations
  67. CONCAM null result on GRB001005
  68. Public availability of BeppoSAX data of GRB000926
  69. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  70. GRB000926 - Optical observations
  71. GRB 000926, Optical Observations
  72. GRB000911: optical VLT observations
  73. GRB000926 K'-band Observation
  74. GRB 000926, optical observation by Oksanen (vsnet-grb)
  75. Spectroscopic Redshift of GRB 000926
  76. GRB000926, radio observations
  77. GRB 000926: Optical candidate
  78. Optical candidate for GRB000926
  79. GRB 000830: Optical observations
  80. GRB000801 & GRB000730, Gamma Ray Observations
  81. GRB 000727, optical observations
  82. IPN localization of GRB000727
  83. GRB 990712: Late time HST/STIS Observations
  84. GRB000630, optical observations
  85. GRB000630, optical observations
  86. GRB000630, optical observations
  87. GRB000630: Optical observations
  88. GRB000630, Radio Observations
  89. GRB000418, HST/STIS Observations
  90. GRB990123: Late-time HST/STIS observations of the host
  91. GRB000620, optical observations
  92. GRB000615: H-band observations
  93. GRB000620: BeppoSAX WFC and GRBM detection
  94. GRB000607, optical observations
  95. GRB 000615: NIR further observations
  96. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  97. The Hosts of GRB 980703 and GRB 971214
  98. GRB 000301C: Further Late-Time HST/STIS observations
  99. GRB000528: follow-up X-ray measurements and update of IPN annulus
  100. Optical Follow-up of GRB000529 Error Box

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