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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"

42583 results found.

  1. GRB030429, BVRcIc field photometry
  2. GRB030429: RTT150 optical obs., correction to GCN 2208
  3. GRB 030329: High-Resolution Spectroscopy of the Host
  4. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  5. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  6. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  7. GRB030429: RTT150 optical observations, a possible host galaxy
  8. IPN triangulation of GRB030506 (annulus)
  9. IPN triangulation of GRB030505B (large error box)
  10. IPN triangulation of GRB030505A (annulus)
  11. GRB030329: RTT150 optical observations and upper limit for a host
  12. GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
  13. GRB030501 observation report
  14. GRB030501C triangulation (annulus)
  15. GRB030329: RTT150 optical observations and upper limit for a host
  16. GRB 030429: Radio Observations
  17. GRB 030429: redshift from VLT spectroscopy
  18. GRB030501B triangulation (single error box)
  19. GRB 030329 Optical Observations
  20. GRB030328, optical observation
  21. GRB 030329, BVRI photometry
  22. GRB030429: Optical Observations
  23. GRB030501: TAROT candidate afterglow present in archival images
  24. GRB 030501: TAROT possible candidate counterpart
  25. IPN triangulation of GRB030501 (IBIS event; annulus)
  26. IPN triangulation of GRB030501B (annulus)
  27. GRB 030429: confirmation of afterglow candidate
  28. GRB030429, possible optical counterpart
  29. GRB030501 localized by INTEGRAL
  30. GRB030425: CrAO optical observation
  31. IPN triangulation of GRB030429 (annulus)
  32. IPN triangulation of GRB030428 (two large error boxes)
  33. GRB 030429: ROTSE-III observations
  34. GRB 030324: Radio Observations
  35. GRB030329 observed as a sudden ionospheric disturbance (SID)
  36. IPN triangulation of GRB030426 (annulus)
  37. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  38. IPN triangulation of GRB030425 (single error box)
  39. GRB030329, SPM optical observations (Correction)
  40. GRB030329, SPM optical observations
  41. GRB 030329: Spectral Evolution of SN 2003dh
  42. Optical Observations of GRB 030418 with Magellan
  43. GRB 030329: optical spectropolarimetry at VLT
  44. IPN triangulation of GRB030422C (annulus)
  45. IPN triangulation of GRB030422B (annulus)
  46. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  47. GRB030329: optical polarization
  48. IPN triangulation of GRB030422 (two large error boxes)
  49. GRB 030329 3.5 and 6 cm radio observations at RTF-32 telescope
  50. GRB030329, optical observation
  51. IPN triangulation of GRB030421 (annulus)
  52. MASTER:optical observations GRB030418
  53. MASTER:optical observations probable GRB030414
  54. GRB030329: 444 AAVSO Measurements
  55. IPN triangulation of GRB030419 (annulus)
  56. MASTER:optical observations GRB030416
  57. ROTSE-III prompt optical detections of GRB 030418
  58. GRB030418: Upper limits from recent and historical observations.
  59. GRB 030418: Finder for afterglow candidate
  60. GRB 030418: Optical afterglow candidate
  61. GRB 030329 OT position
  62. GRB030329: Optical Observations
  63. OT GRB 030329: early UBVRcIc spectral evolution
  64. GRB030329, UBVRI polarimetry, R-polarization
  65. GRB 030329: SARA Optical Observations
  66. OT GRB 030329: early spectrum
  67. GRB030329: VR Photometry at TNG
  68. GRB030324: Candidate Optical Afterglow
  69. IPN triangulation of GRB030414 (small error box)
  70. GRB 030413: Optical Observations
  71. GRB 030329 Rc observations
  72. IPN triangulation of GRB030413 (small error box)
  73. IPN triangulation of GRB030410 (annulus)
  74. Superluminal motion in GRB 030329 (Correction)
  75. Superluminal motion in GRB 030329
  76. GRB 030329 and SN 2003dh
  77. GRB030329, optical position
  78. GRB 030329 VLBA Observations
  79. IPN triangulation of GRB030406 (small error box)
  80. IPN triangulation of GRB050403 (small error box)
  81. IPN triangulation of GRB030403 (annulus)
  82. GRB 030329: BVRI photometry at Asiago
  83. GRB 030329, light curve flattens
  84. GRB 030329: VLT V-band photometry
  85. If the SN/GRB connection confirmed
  86. GRB 030329: Supernova Confirmed
  87. GRB030329: RTT150 optical observations
  88. GRB030329: HET spectroscopic monitoring
  89. GRB 030329, color evolution
  90. GRB030328, UBVRcIc field photometry
  91. GRB030329: Optical observcations
  92. GRB030329: BV photographic observations
  93. GRB 030329, color evolution
  94. GRB030329: RTT150 optical observations
  95. GRB 030329: Supernova Spectrum Emerging
  96. GRB030329: RTT150 optical observation
  97. GRB030329: More AAVSO VR obs
  98. GRB030328: R upper limit after 6 hours by MASTER
  99. GRB 030329: SARA Optical Observations
  100. GRB 030329: SARA Optical Observations

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