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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"

41189 results found.

  1. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  2. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  3. Spectropolarimetry of GRB021004
  4. GRB021104: Optical observations
  5. GRB021104: optical observations
  6. GRB021104: Candidate present in DSS
  7. GRB021104: possible optical afterglow
  8. Detection of activity from SGR 1900+14 with the RXTE/PCA
  9. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  10. GRB021004, late-time optical observations
  11. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  12. IPN triangulation of GRB021025 (annulus)
  13. GRB 021004: optical observations
  14. GRB021004: Optical Observations
  15. GRB 020813; likely host galaxy.
  16. IPN triangulation of GRB021020 (smaller error box)
  17. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  18. GRB 021016, optical observations
  19. GRB 021004: VRI observations at TNG: possible break
  20. GRB021016, optical observations
  21. SGR1900+14: burst on October 10 2002
  22. GRB 021008, optical observations
  23. GRB021016(=H2397): A Long GRB Localized by HETE
  24. IPN triangulation of GRB021016 (small error box)
  25. GRB021004: Optical Observations
  26. GRB 021004: optical spectroscopy on Oct 11
  27. IPN triangulation of GRB021013 (two small error boxes)
  28. GRB021004: High-resolution optical spectroscopy
  29. IPN triangulation of GRB021013 (annulus)
  30. XRF 020903: flattening of the optical light curve.
  31. GRB021004, UBVRcIc field photometry update
  32. GRB021004: Optical Observations
  33. GRB 021004 submm observations
  34. IPN triangulation of GRB021008B (annulus)
  35. GRB021004 Chandra HETG Observations
  36. GRB 021004: Optical/NIR Observations
  37. GRB 021004: Additional V-band Polarimetric Observations
  38. GRB021004: optical observation
  39. GRB 021004: Host Galaxy Star Formation Rate
  40. GRB 021004 submm observations
  41. GRB 021004: WC wind?
  42. IPN triangulation of GRB021008
  43. GRB021004: NIR and Optical observations
  44. GRB 021004: Optical measurement at OHP
  45. GRB 021004: Optical observations, AUDE network
  46. GRB 021004 - VLA Radio Observations
  47. GRB 021004 - Unusual Radio-to-Submm Spectrum
  48. GRB 021004: optical spectroscopy
  49. IPN triangulation of GRB021007 (annulus)
  50. XRF 020903 spectrum
  51. GRB 021004: HST/STIS spectroscopic observations
  52. GRB021004: optical observations and predicted break time
  53. GRB021004: BVRc photometry
  54. GRB 021004 redshift
  55. GRB021004 radio observation
  56. GRB021004: restart of optical decay
  57. GRB 021004: Optical Decay
  58. GRB 021004 continued IR fading
  59. HETE fluences for GRB021004
  60. GRB 021004, spectroscopic observations
  61. GRB021004: not fading anymore?
  62. GRB 021004: Optical Photometry at 2.5 Days
  63. GRB 021004: polarimetric observations
  64. GRB 021004: V-band Polarimetric Observations
  65. GRB 021004: Optical Decay
  66. GRB021004, astrometric position
  67. GRB021004, Optical Observations
  68. IRAM Millimeter detection of GRB 021004
  69. GRB 021004: Optical observations at RIKEN
  70. GRB 021004 radio observation
  71. GRB 021004: Optical Observations
  72. GRB021004: continued fading
  73. GRB 021004: Optical Photometry at 1.5 Days
  74. GRB021004, Optical Observations
  75. GRB021004, BVRcIc field photometry
  76. GRB 021004: Optical observations
  77. GRB 021004: optical counterpart
  78. GRB 021004, optical observations
  79. GRB021004: Optical Spectroscopy
  80. GRB 021004: Optical Observations
  81. GRB 021004, SPM optical observations
  82. GRB 021004, optical observations
  83. GRB 021004 radio search
  84. GRB 021004: radio observations
  85. GRB 021004: steepening of the optical decay slope
  86. GRB021004: Upper limits from recent and historical observations
  87. XRF020903, BVRI field photometry
  88. GRB021004: optical observations at Nyrola
  89. GRB021004: Absorption redshift
  90. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  91. GRB021004: optical observations at Bisei
  92. GRB 021004: Kyoto observation
  93. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  94. GRB021004: Optical Afterglow
  95. XRF020903: TNG and Asiago photometry
  96. GRB 020903: Optical observations at RIKEN
  97. XRF 020903: Correction to GCN 1560
  98. XRF 020903: VRI observations
  99. IPN triangulation of GRB020926 (single large error box)
  100. XRF 020903: R band observations

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