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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').
  1. GRB021104: Optical observations
  2. GRB021104: optical observations
  3. GRB021104: Candidate present in DSS
  4. GRB021104: possible optical afterglow
  5. IPN triangulation of GRB021102 (annulus)
  6. Detection of activity from SGR 1900+14 with the RXTE/PCA
  7. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  8. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  9. IPN triangulation of GRB021025 (portion of annulus)
  10. IPN triangulation of GRB021027 (single large error box)
  11. GRB021004, late-time optical observations
  12. IPN triangulation of GRB021027 (two large error boxes)
  13. GRB 021023: Infrared Imaging
  14. IPN triangulation of GRB021027 (annulus)
  15. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  16. IPN triangulation of GRB021025 (annulus)
  17. IPN triangulation of SGR1900+14, October 22 2002
  18. GRB 021004: optical observations
  19. IPN triangulation of GRB021023 (small error boc)
  20. GRB021004: Optical Observations
  21. GRB 020813; likely host galaxy.
  22. IPN triangulation of GRB021020 (smaller error box)
  23. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  24. IPN triangulation of GRB021020
  25. GRB 021008, radio observations
  26. GRB 021016, optical observations
  27. GRB 021004: VRI observations at TNG: possible break
  28. GRB021016, optical observations
  29. SGR1900+14: burst on October 10 2002
  30. GRB 021008, optical observations
  31. GRB021016(=H2397): A Long GRB Localized by HETE
  32. IPN triangulation of GRB021016 (area corrected)
  33. IPN triangulation of GRB021016 (small error box)
  34. GRB021004: Optical Observations
  35. IPN triangulation of GRB021014 (large error box)
  36. IPN triangulation of GRB021013 (single error box)
  37. GRB 021004: optical spectroscopy on Oct 11
  38. IPN triangulation of GRB021013 (two small error boxes)
  39. GRB021004: High-resolution optical spectroscopy
  40. IPN triangulation of GRB021013 (annulus)
  41. XRF 020903: flattening of the optical light curve.
  42. GRB021004, UBVRcIc field photometry update
  43. IPN triangulation of GRB021008 (single error box)
  44. GRB021004: Optical Observations
  45. GRB 021004 submm observations
  46. IPN triangulation of GRB021008B (annulus)
  47. IPN triangulation of GRB021008 (two small error boxes)
  48. GRB021004 Chandra HETG Observations
  49. GRB 021004: Optical/NIR Observations
  50. GRB 021004: Additional V-band Polarimetric Observations
  51. GRB021004: optical observation
  52. GRB 021004: Host Galaxy Star Formation Rate
  53. GRB 021004 submm observations
  54. GRB 021004: WC wind?
  55. IPN triangulation of GRB021008
  56. GRB021004: NIR and Optical observations
  57. GRB 021004: Optical measurement at OHP
  58. GRB 021004: Optical observations, AUDE network
  59. GRB 021004 - VLA Radio Observations
  60. GRB 021004 - Unusual Radio-to-Submm Spectrum
  61. GRB 021004: optical spectroscopy
  62. IPN triangulation of GRB021007 (annulus)
  63. XRF 020903 spectrum
  64. GRB 021004: HST/STIS spectroscopic observations
  65. GRB021004: optical observations and predicted break time
  66. GRB021004: BVRc photometry
  67. GRB 021004 redshift
  68. GRB021004 radio observation
  69. GRB021004: restart of optical decay
  70. GRB 021004: Optical Decay
  71. GRB 021004 continued IR fading
  72. HETE fluences for GRB021004
  73. GRB 021004, spectroscopic observations
  74. GRB021004: not fading anymore?
  75. GRB 021004: Optical Photometry at 2.5 Days
  76. GRB 021004: polarimetric observations
  77. GRB 021004: V-band Polarimetric Observations
  78. GRB021004: Update Bisei photometric data
  79. GRB 021004: Optical Decay
  80. GRB021004, astrometric position
  81. GRB021004, Optical Observations
  82. IRAM Millimeter detection of GRB 021004
  83. GRB 021004: Optical observations at RIKEN
  84. GRB 021004 radio observation
  85. GRB 021004: Optical Observations
  86. GRB021004: continued fading
  87. GRB 021004: Optical Photometry at 1.5 Days
  88. GRB021004, Optical Observations
  89. GRB021004, BVRcIc field photometry
  90. GRB 021004: Optical observations
  91. GRB 021004: optical counterpart
  92. GRB 021004, optical observations
  93. GRB021004: Optical Spectroscopy
  94. GRB 021004: Optical Observations
  95. GRB 021004, SPM optical observations
  96. GRB 021004, optical observations
  97. GRB 021004 radio search
  98. GRB 021004: radio observations
  99. GRB 021004: steepening of the optical decay slope
  100. GRB021004: Upper limits from recent and historical observations

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