GRB Too observations in Loiano

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GRB Too observations in Loiano

• Patrizia Ferrero
• (IASF-BO, OACT Universita di Teramo)

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Our collaboration

• Patrizia Ferrero
• (IASF-BO, OACT Universita di Teramo)
• Corrado Bartolini, Adriano Guarnieri, Adalberto
  Piccioni
• (Universita di Bologna)
• Graziella Pizzichini
• (IASF-BO)

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The 152 cm telescope in Loiano
General description of the 152 cm
telescope Optical configuration
Ritchey-Chretien Mount Type English Total
weight 9000 Kg Main concave mirror total
diameter 152.4 cm useful diameter 150.0 cm
focal ratio F/3 Secondary mirror total
diameter 58.0 cm useful diameter 55.5 cm
Mirror distance 308.7 cm Cassegrain Focus
equivalent focal length 1200 cm equivalent
focal ratio F/8 scale 17"/mm useful corrected
field 70'

• We use the Cassini Telescope equipped with the
  BFOSC (Bologna Faint Object Spectrograph
  Camera) to acquire CCD frames.
• The detector is an EEV CCD with an array of
  1300x1340 pixels and its main features are
• quantum efficiency 80 _at_ 500 nm, 32 _at_ 900 nm,
  gt50 _at_ 300 nm
• pixel size 20x20 micron
• pixel scale 0.58 arcsec/pixel
• field of view 12.6x13
• read-out noise 1.73 e-/px
• conversion factor 2.13 e-/ADU.
• At present UBVRI Johnson-Kron-Cousin and GRZI
  Thuan-Gunn filters can be mounted.

The 152 cm Cassini telescope of the Bologna
Astronomical Observatory is located in Loiano,
about 40 Km south of Bologna. The location is
Lat. 44d 15 30 N, Long. 11d 20 12 E,
altitude 785 m a.s.l..
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Summary of our observational activity in Loiano

• From mid-2001 to October 2004, it was possible to
  observe 18 Gamma-Ray Burst locations. In this
  period the GRB events were more than 18, but our
  observations are limited by
• bad weather
• GRB coordinates in order to avoid telescope
  optics stress, we cannot observe the objects
  which have Declination less than -10 degrees
• GRB error boxes we dont analyse error boxes
  which are greater than about 40 x 30

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• target of opportunity program every semestr we
  have six nights to observe GRB locations and
  these observations have to be compatible with the
  scheduled ones and the telescope instruments
  (BFOSC).
• We had
• positive detections (i.e. we detected the optical
  afterglow) for GRB 020813, 021004, 030226,
  030328, 030329, 030418, 041006 and
• negative detections for GRB 020317, 020812,
  020819, 030217, 030227, 030324, 030418, 040422,
  040624, 040825a and 040825b.

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Images Analysis

• To reduce our images and do photometry, we use
• IRAF Image Reduction and Analysis Facility
• while to astrometrize
• GAIA Graphical Astronomy and Image Analysis Tool

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GCNs which include our observations
The GRB Coordinates Network (http//gcn.gsfc.na
sa.gov/)
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• And now some examples of our observations and
  results. . .

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GRB040825a
N

• R.A. 22h 58m 59s and Declination -10d 56 01
  (center of the error box)
• Mean time of observations August 26.035 UT,
  21.336 hours after the GRB
• Magnitude limit Rc19.5 our limit is the first
  in Rc filter
• GCN 2664
• In GCN 2661 Tristram et al. reported R(similar
  to Ic)21.1

E
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GRB040825b

• R.A.22h 46m 34s and Declination-02d 24 27
  (center of error box)
• R.A. 22h 46m 40s and Declination -02d 21 42
  (center of our 1st subfield of the error box)
• R.A. 22h 46m 38s and Declination -02d 28
  (center of our 2nd subfield of the error box)
• Mean Time of observations August 25.975 UT,
  7.050 hours after the GRB
• Magnitude limit Rc19.5
• GCN 2663

N
E
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GRB030418
N

• Mean Time of observations April OT R.A. 10h
  54m 34s and Declination -07d 01 40
• 18.85411 UT, 10.5219 hours after the GRB
• OT magnitude Rc20.5/-0.3, Rc20.7/-0.3
  Ic19.8 /-0.2
• GCN 2284

E
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GRB030328
N

• OT R.A. 12h 10m 48s and Declination -09d 20
  51
• Mean Time of observations March 28.93889 UT,
  11.184 hours after the GRB
• OT magnitude Rc20.32 /- 0.10
  Rc20.30/-0.08
• GCN 2008

E
13
GRB030226
N

• OT R.A. 11h 33m 05s and Declination 25d 53
  56
• Mean Time of observations February 27.160718
  UT, 20.484 hours after the GRB
• OT magnitude Rc19.9/ 0.1, Ic19.6/-0.2,
  V20.50 /-0.05, B21.44/-0.10
• GCN 1892 1940

E
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GRB021004
N

• OT R.A. 00h 26m 55s and Declination 18d 55
  41
• Mean Time of observations October 6.05294 UT
  7.90313 UT, respectively 37.1674 and 81.5712
  hours after the GRB
• OT magnitude Rc19.69/ 0.13, Ic19.3/-0.2,
  V19.99 /-0.12, B20.63/-0.13
• GCN 1603

E
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The Future......
Hete-2 and Integral satellites are expected to
continue their activity of detection of gamma ray
bursts, while the imminent launch of Swift should
lead to almost 1 GRB/day with a faster
localization of the optical afterglow due to the
on board telescope, which can automatically
re-point toward the burst direction, and a more
intense observational activity of all
observatories, Loiano included.
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• The end.