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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"

10761 results found.

  1. GRB030226: Candidate optical afterglow
  2. GRB 030217: Optical Observations at 4, 5, and 6 Days
  3. GRB030217: optical observations
  4. GRB030131: Kiso optical limit for corrected position
  5. GRB030131: Optical limits for corrected position
  6. GRB 030131: afterglow candidate
  7. GRB030131: Optical limit
  8. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  9. GRB 030115, simultaneous observations by BOOTES-1
  10. GRB030115: R-band counterpart of IR candidate
  11. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  12. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  13. GRB030115: R-band observations at Asiago
  14. GRB 030115: APO Optical Observations
  15. GRB 030115, no optical candidate
  16. IPN triangulation of GRB030102B (portion of annulus)
  17. GRB on 20030101 seen by SPI-ACS
  18. IPN triangulation of GRB021219
  19. GRB021219: a long GRB localized by INTEGRAL
  20. IPN detection of continued activity from SGR1806-20
  21. GRB 021201: Optical Observations
  22. GRB 021211: early break in light curve
  23. GRB021211: Optical observations in CrAO
  24. Chandra observation of the IPN error box of GRB021201 (short/hard)
  25. GRB 021211 Milagro GeV/TeV Observations
  26. GRB021211, OT at 108 s
  27. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  28. HETE 2493: Optical observations
  29. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  30. IPN detection of renewed activity from SGR1806-20
  31. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  32. IPN detection of continued SGR1900+14 activity
  33. Improved IPN error box for GRB021125
  34. GRB021125 : A long GRB localized by INTEGRAL
  35. IPN confirmation of the reactivation of SGR1900+14
  36. IPN detection of possible reactivation of SGR1900+14
  37. IPN triangulation of GRB021119 (annulus)
  38. GRB021112: Optical Observations
  39. GRB021113 (=H2449): A Long GRB Localized by HETE
  40. GRB021112 (=H2448): A Long GRB Localized by HETE
  41. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  42. SGR1900+14 activity, November 2-4, 2002
  43. Detection of activity from SGR 1900+14 with the RXTE/PCA
  44. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  45. GRB 021004: optical observations
  46. IPN triangulation of GRB021020 (smaller error box)
  47. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  48. IPN triangulation of GRB021020
  49. GRB 021016, optical observations
  50. GRB 021004: VRI observations at TNG: possible break
  51. GRB 021008, optical observations
  52. GRB021016(=H2397): A Long GRB Localized by HETE
  53. GRB021004: NIR and Optical observations
  54. GRB 021004: Optical measurement at OHP
  55. GRB 021004: optical spectroscopy
  56. GRB021004: BVRc photometry
  57. GRB 021004: Optical Photometry at 2.5 Days
  58. GRB 021004 radio observation
  59. GRB 021004: Optical Observations
  60. GRB 021004: Optical Photometry at 1.5 Days
  61. GRB021004, Optical Observations
  62. GRB 021004, optical observations
  63. GRB 021004, SPM optical observations
  64. GRB 021004: steepening of the optical decay slope
  65. XRF020903, BVRI field photometry
  66. GRB 020903: Optical observations at RIKEN
  67. XRF 020903: Supernova
  68. IPN triangulation of GRB020926 (two large error boxes)
  69. GRB020924 (ecliptic latitude-only localization)
  70. IPN triangulation of GRB020923 (two error boxes)
  71. Improved IPN position for GRB020918 (two large error boxes)
  72. IPN triangulation of GRB020911 (2 large error boxes)
  73. IPN detection of a burst from SGR1900+14
  74. INTEGRAL GRBs added to GCN
  75. GRB020812: optical observation
  76. Second epoch K band imaging of GRB 020819
  77. GRB 020812: early time optical observation at Ouda Station
  78. GRB020813: Magellan BVRI Photometry
  79. GRB 020819 : OT candidate - confirmation of non variability
  80. K band observation of GRB 020819
  81. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  82. IPN triangulation of GRB020819 (HETE 2275)
  83. GRB020813: Fading X-ray Afterglow Observed with Chandra
  84. GRB020812: NIR observations
  85. GRB020812: optical observations
  86. GRB 020812 : optical afterglow candidate
  87. GRB020813, optical observations
  88. GRB 020812 optical observation
  89. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  90. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  91. GRB020801, optical afterglow candidate
  92. IPN triangulation of GRB020714
  93. GRB 020410: Discovery of Probable OT by HST
  94. Correction to IPN error box for GRB020706
  95. IPN triangulation of GRB020706
  96. GRB 020705: Optical observations
  97. GRB020625 (=H2081): A Long Burst Localized by HETE
  98. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  99. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  100. AXP 1E2259+586: quasi-simultaneous optical observation

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