GRB 150219A

S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo 
(ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS 
Localization Team report:

a gamma ray burst lasting about 60 s has been detected by IBAS in the 
IBIS/ISGRI data at 12:31:14 UT of February 19

The refined coordinates (J2000) are:

R.A.= 271.2664  deg
DEC.=  -41.5849 deg

with an uncertainty of 2 arcmin (90% c.l.).

The burst had a peak flux of 1.4 counts/cm2/s (20-200 keV, 1-s integration 
time) and a fluence in the same energy range of about 4e-6 erg/cmq.

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a ToO observation of the INTEGRAL GRB 150219A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020483

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the INTEGRAL event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.

K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea
(PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore
(U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the INTEGRAL-detected
burst GRB 150219A (Mereghetti et al. GCN Circ. 17476
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 ), collecting 2.6
ks of Photon Counting (PC) mode data between T0+10.5 ks and T0+23.4 ks.


An uncatalogued X-ray source is detected inside the INTEGRAL error
region and is fading with 3-sigma significance, and is therefore likely
the GRB afterglow.  The position of this source is RA, Dec=271.2507,
-41.5942 which is equivalent to:

RA (J2000): 18:05:0.18
Dec(J2000): -41:35:39.0

with an uncertainty of 3.7 arcsec (radius, 90% confidence).  This
position is 53 arcsec from the INTEGRAL position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.8 (+0.9, -0.7).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.8 (+/-0.4). The
best-fitting absorption column is  1.6 (+0.6, -0.5) x 10^22 cm^-2, in
excess of the Galactic value of 1.4 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 6.3 x 10^-11 (1.1 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.6 (+0.6, -0.5) x 10^22 cm^-2
Galactic foreground: 1.4 x 10^21 cm^-2
Excess significance: 4.6 sigma
Photon index:	     1.8 (+/-0.4)

If the light curve continues to decay with a power-law decay index of
2.8, the count rate at T+24 hours will be 5.8 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.6 x
10^-14 (6.2 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020483/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020483.

This circular is an official product of the Swift-XRT team.

A. von Kienlin (MPE) and C. Meegan (UAH) 
report on behalf of the Fermi GBM Team:

"At 12:31:12.26 UT on 19 February 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150219A (trigger 446041875 / 150219522), which
was also detected by INTEGRAL/IBIS (Mereghetti  et al. 2015, GCN 17476
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 ).
The GBM on-ground location is consistent with the INTEGRAL position.

The angle from the Fermi LAT boresight is 105 degrees.

The GBM light curve shows a structured pulse
with a duration (T90) of about 36 s (50-300 keV).
The time-averaged spectrum from T0-2.304 s to T0+38.657 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.92 (+0.08/-0.07)  and
the cutoff energy, parameterized as Epeak, is 202.7(+23.2/-19.1) keV.

The event fluence (10-1000 keV) in this time interval is
(1.00 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+9.664 s in the 10-1000 keV band
is 4.2 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak=
166.7(+24.3/-17.3) keV, 
alpha = -0.82 +/- 0.10 and beta = -2.17 (+0.13/-0.24).

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."