scholarly journals AGILE, Fermi, Swift, and GASP/WEBT multi-wavelength observations of the high-redshift blazar 4C +71.07 in outburst

2019 ◽  
Vol 621 ◽  
pp. A82 ◽  
Author(s):  
S. Vercellone ◽  
P. Romano ◽  
G. Piano ◽  
V. Vittorini ◽  
I. Donnarumma ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Near Infrared ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
High Mass ◽  
Spectral Energy ◽  
Emission Region ◽  
Energy Bands ◽  
Spectrum Radio

Context. The flat-spectrum radio quasar 4C +71.07 is a high-redshift (z = 2.172), γ-loud blazar whose optical emission is dominated by thermal radiation from the accretion disc. Aims. 4C +71.07 has been detected in outburst twice by the AGILE γ-ray satellite during the period from the end of October to mid-November 2015, when it reached a γ-ray flux of the order of F(E >  100 MeV)=(1.2 ± 0.3)×10−6 photons cm−2 s−1 and F(E > 100 MeV)=(3.1 ± 0.6)×10−6 photons cm−2 s−1, respectively, allowing us to investigate the properties of the jet and the emission region. Methods. We investigated its spectral energy distribution by means of almost-simultaneous observations covering the cm, mm, near-infrared, optical, ultraviolet, X-ray, and γ-ray energy bands obtained by the GASP-WEBT Consortium and the Swift, AGILE, and Fermi satellites. Results. The spectral energy distribution of the second γ-ray flare (whose energy coverage is more dense) can be modelled by means of a one-zone leptonic model, yielding a total jet power of about 4 × 1047 erg s−1. Conclusions. During the most prominent γ-ray flaring period our model is consistent with a dissipation region within the broad-line region. Moreover, this class of high-redshift, flat-spectrum radio quasars with high-mass black holes might be good targets for future γ-ray satellites such as e-ASTROGAM.

IGR J16318-4848: optical and near-infrared spectroscopy of the most absorbed B[e] supergiant X-ray binary with VLT/X-Shooter

2018 ◽  
Vol 14 (S346) ◽  
pp. 152-157
Author(s):  
F. Fortin ◽  
S. Chaty ◽  
P. Goldoni ◽  
A. Goldwurm
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
High Mass ◽  
Binary Interaction ◽  
Spectral Energy ◽  
Emission Region ◽  
Geometrical Parameters ◽  
Distribution Fitting ◽  
X Ray ◽  
Wide Range

AbstractThe supergiant high-mass X-ray binary IGR J16318-4848 was detected by INTEGRAL in 2003 and distinguishes itself by its high intrinsic absorption and B[e] phenomenon. It is the perfect candidate to study both binary interaction and the environment of supergiant B[e] stars. We report on VLT/X-Shooter observations from July 2012 in both optical and near-infrared, which provide unprecedented wide-range, well-resolved spectra of IGR J16318-4848 from 0.5 to 2.5 μm. Adding VLT/VISIR and Herschel data, the spectral energy distribution fitting allows us to further constrain the contribution of each emission region (central star, irradiated rim, dusty disc). We derive geometrical parameters using the numerous emitting and absorbing elements in each different sites in the binary. Various line shapes are detected, such as P-Cygni profiles and flat-topped lines, which are the signature of outflowing material. Preliminary results confirm the edge-on line of sight and the equatorial configuration of expanding material, along with the detection of a potentially very collimated polar outflow. These are evidence that the extreme environment of IGR J16318-4848 is ideal to have a better grasp of highly obscured high-mass X-ray binaries.

scholarly journals A review of spectral energy distribution modeling at high-redshift

2019 ◽  
Vol 15 (S352) ◽  
pp. 77-77
Author(s):  
Stéphane Charlot
Keyword(s):  
Interstellar Medium ◽  
Energy Distribution ◽  
Rest Frame ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
Spectral Energy ◽  
Distribution Modeling ◽  
Redshift Galaxy ◽  
Recent Developments

AbstractI will review recent developments in the modeling of high-redshift galaxy spectra, focusing in particular on the rest-frame ultraviolet and optical emission from young stellar populations and the interstellar medium.

scholarly journals Revised SED of the triple protostellar system VLA 1623−2417

2018 ◽  
Vol 615 ◽  
pp. L14 ◽  
Author(s):  
N. M. Murillo ◽  
D. Harsono ◽  
M. McClure ◽  
S.-P. Lai ◽  
M. R. Hogerheijde
Keyword(s):  
Energy Distribution ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Gas Emission ◽  
Circumstellar Gas ◽  
Infrared Wavelengths ◽  
Previous Assumption

Context. VLA 1623−2417 is a triple protostellar system deeply embedded in Ophiuchus A. Sources A and B have a separation of 1.1″, making their study difficult beyond the submillimeter regime. Lack of circumstellar gas emission suggested that VLA 1623−2417 B has a very cold envelope and is much younger than source A, which is generally considered the prototypical Class 0 source. Aims. We explore the consequences of new ALMA Band 9 data on the spectral energy distribution (SED) of VLA 1623−2417 and their inferred nature. Methods. We constructed and analyzed the SED of each component in VLA 1623−2417 using dust continuum observations spanning from centimeter to near-infrared wavelengths. Results. The ALMA Band 9 data presented in this work show that the SED of VLA 1623−2417 B does not peak at 850 µm as previously expected, but instead presents the same shape as VLA 1623−2417 A at wavelengths shorter than 450 µm. Conclusions. The results presented in this work indicate that the previous assumption that the flux in Herschel and Spitzer observations is solely dominated by VLA 1623−2417 A is not valid, and instead, VLA 1623−2417 B most likely contributes a significant portion of the flux at λ < 450 µm. These results, however, do not explain the lack of circumstellar gas emission and puzzling nature of VLA 1623−2417 B.

scholarly journals Serendipitous discovery of an “ALMA-only” galaxy at 5 < z < 6 in an ALMA 3-mm survey

2019 ◽  
Vol 15 (S352) ◽  
pp. 194-198
Author(s):  
Christina C. Williams
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Star Formation Rate ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Large Contribution ◽  
Massive Galaxies ◽  
Multi Wavelength

AbstractWe discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (2019). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs (“ALMA-only”). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr−1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.

scholarly journals Exploring the dimming event of RW Aurigae A through multi-epoch VLT/X-shooter spectroscopy

2019 ◽  
Vol 625 ◽  
pp. A49 ◽  
Author(s):  
M. Koutoulaki ◽  
S. Facchini ◽  
C. F. Manara ◽  
A. Natta ◽  
R. Garcia Lopez ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Physical Properties ◽  
Near Infrared ◽  
Accretion Rate ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Infrared Excess ◽  
Mass Accretion Rate ◽  
Near Ir ◽  
T Tauri

Context. RW Aur A is a classical T Tauri star that has suddenly undergone three major dimming events since 2010. The reason for these dimming events is still not clear. Aims. We aim to understand the dimming properties, examine accretion variability, and derive the physical properties of the inner disc traced by the CO ro-vibrational emission at near-infrared wavelengths (2.3 μm). Methods. We compared two epochs of X-shooter observations, during and after the dimming. We modelled the rarely detected CO bandhead emission in both epochs to examine whether the inner disc properties had changed. The spectral energy distribution was used to derive the extinction properties of the dimmed spectrum and compare the infrared excess between the two epochs. Lines tracing accretion were used to derive the mass accretion rate in both states. Results. The CO originates from a region with physical properties of T = 3000 K, NCO = 1 × 1021 cm−2 and vk sin i = 113 km s−1. The extinction properties of the dimming layer were derived with the effective optical depth ranging from τeff ~2.5−1.5 from the UV to the near-IR. The inferred mass accretion rate Ṁacc is ~1.5 × 10−8 M⊙ yr−1 and ~2 × 10−8 M⊙ yr−1 after and during the dimming respectively. By fitting the spectral energy distribution, additional emission is observed in the infrared during the dimming event from dust grains with temperatures of 500–700 K. Conclusions. The physical conditions traced by the CO are similar for both epochs, indicating that the inner gaseous disc properties do not change during the dimming events. The extinction curve is flatter than that of the interstellar medium, and large grains of a few hundred microns are thus required. When we correct for the observed extinction, the mass accretion rate is constant in the two epochs, suggesting that the accretion is stable and therefore does not cause the dimming. The additional hot emission in the near-IR is located at about 0.5 au from the star and is not consistent with an occulting body located in the outer regions of the disc. The dimming events could be due to a dust-laden wind, a severe puffing-up of the inner rim, or a perturbation caused by the recent star-disc encounter.

scholarly journals A Deep JI Survey of the Pleiades for Freely-Floating Superplanets and Brown Dwarfs at the Deuterium Burning Limit

2003 ◽  
Vol 211 ◽  
pp. 185-186
Author(s):  
M. J. Schwartz ◽  
E. E. Becklin ◽  
B. Zuckerman
Keyword(s):  
Energy Distribution ◽  
Proper Motion ◽  
Near Infrared ◽  
Profile Analysis ◽  
Spectral Energy Distribution ◽  
Brown Dwarfs ◽  
Spectral Energy ◽  
Preliminary Results ◽  
Methane Absorption ◽  
Lower Limits

We present preliminary results from a deep near-infrared J-band and I-band photometric survey of the Pleiades for freely-floating superplanets and brown dwarfs (BD) near the deuterium burning limit (DBL). With limiting magnitudes of J=20.5 and I=23.5, we have selected candidate Pleiads on the basis of evolutionary tracks, color-magnitudes, and I-J color lower limits (non-detections at deep I-band). Likelihoods of membership will be ultimately determined by a combination of image profile analysis, spectral energy distribution, proper motion, and low-resolution measurements of near-infrared water and/or methane absorption slopes. If confirmed, our faintest candidates are predicted to have made the transition from L to T spectral types with temperatures down to 820 K, and masses approaching 10 MJup.

scholarly journals Nature of the Dusty S-cluster Object (DSO/G2): Pre-main-sequence star with non-spherical dusty envelope

2016 ◽  
Vol 11 (S322) ◽  
pp. 231-232
Author(s):  
M. Zajaček ◽  
M. Valencia-S. ◽  
B. Shahzamanian ◽  
F. Peissker ◽  
A. Eckart ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Main Sequence ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Main Sequence Star ◽  
Continuum Emission ◽  
Spectral Energy ◽  
Galactic Centre ◽  
Infrared Excess ◽  
Sgr A

AbstractNear-infrared observations reveal several infrared-excess sources near the Galactic Centre with emission lines present in their spectra. One of these objects, DSO/G2, which moves around the supermassive black hole (Sgr A*) on a highly eccentric orbit, passed the pericentre at approximately 160 AU in 2014. It remained compact, which implies that at least in this case it is a star embedded in a dusty envelope. The spectral energy distribution and the detection of polarized continuum emission indicate that it is probably a pre-main-sequence star surrounded by a dense envelope with bipolar cavities. In addition, the star associated with DSO/G2 plausibly develops a bow shock due to its supersonic motion. The model of the star surrounded by the non-spherical dusty envelope can reproduce the main characteristics of the DSO/G2 source: 1. spectral energy distribution in near-infrared bands; 2. linear polarization in Ks band; and 3. the overall compact behaviour.

HIGH-REDSHIFT DUST OBSCURED GALAXIES: A MORPHOLOGY-SPECTRAL ENERGY DISTRIBUTION CONNECTION REVEALED BY KECK ADAPTIVE OPTICS

2009 ◽  
Vol 137 (6) ◽  
pp. 4854-4866 ◽  
Author(s):  
J. Melbourne ◽  
R. S. Bussman ◽  
K. Brand ◽  
V. Desai ◽  
L. Armus ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Adaptive Optics ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Spectral Energy

scholarly journals Simulating JWST deep extragalactic imaging surveys and physical parameter recovery

2020 ◽  
Vol 640 ◽  
pp. A67
Author(s):  
O. B. Kauffmann ◽  
O. Le Fèvre ◽  
O. Ilbert ◽  
J. Chevallard ◽  
C. C. Williams ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Photometric Redshifts ◽  
The Galaxy ◽  
Stellar Masses ◽  
The Impact

We present a new prospective analysis of deep multi-band imaging with the James Webb Space Telescope (JWST). In this work, we investigate the recovery of high-redshift 5 <  z <  12 galaxies through extensive image simulations of accepted JWST programs, including the Early Release Science in the EGS field and the Guaranteed Time Observations in the HUDF. We introduced complete samples of ∼300 000 galaxies with stellar masses of log(M*/M⊙) > 6 and redshifts of 0 <  z <  15, as well as galactic stars, into realistic mock NIRCam, MIRI, and HST images to properly describe the impact of source blending. We extracted the photometry of the detected sources, as in real images, and estimated the physical properties of galaxies through spectral energy distribution fitting. We find that the photometric redshifts are primarily limited by the availability of blue-band and near-infrared medium-band imaging. The stellar masses and star formation rates are recovered within 0.25 and 0.3 dex, respectively, for galaxies with accurate photometric redshifts. Brown dwarfs contaminating the z >  5 galaxy samples can be reduced to < 0.01 arcmin−2 with a limited impact on galaxy completeness. We investigate multiple high-redshift galaxy selection techniques and find that the best compromise between completeness and purity at 5 <  z <  10 using the full redshift posterior probability distributions. In the EGS field, the galaxy completeness remains higher than 50% at magnitudes mUV <  27.5 and at all redshifts, and the purity is maintained above 80 and 60% at z ≤ 7 and 10, respectively. The faint-end slope of the galaxy UV luminosity function is recovered with a precision of 0.1–0.25, and the cosmic star formation rate density within 0.1 dex. We argue in favor of additional observing programs covering larger areas to better constrain the bright end.

scholarly journals Revealing the Nature of the Highly Obscured Galactic Source IGR J16318-4848

2004 ◽  
Vol 194 ◽  
pp. 65-66
Author(s):  
S. Chaty ◽  
P. Filliatre
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Nir Spectroscopy ◽  
High Mass ◽  
Spectral Energy ◽  
X Ray ◽  
Circumstellar Material ◽  
New Class ◽  
Galactic Source ◽  
Early Type Star

AbstractThe X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL on 2003, January 29. We carried out optical and near-infrared (NIR) observations at the European Southern Observatory (ESO La Silla) in the course of a Target of Opportunity (ToO) programme. We discovered the optical counterpart and confirmed an already proposed NIR candidate. NIR spectroscopy revealed a large amount of emission lines, including forbidden iron lines and P-Cygni profiles. The spectral energy distribution of the source points towards a high luminosity and a high temperature, with an absorption greater than the interstellar absorption, but two orders of magnitude lower than the X-ray absorption. We show that the source is an High Mass X-ray binary (HMXB) at a distance between ~ 1 and ~ 6 kpc, the mass donor being an early-type star, probably a sgB[e] star, surrounded by a rich and absorbing circumstellar material. This would make the second High Mass X-ray Binary (HMXB) with a sgB[e] star after CI Cam, indicating that a new class of strongly absorbed X-ray binaries is being unveiled by INTEGRAL.

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