FIDEL CRUZ PEREGRINO | Universidad Autónoma Metropolitana-Azcapotzalco (original) (raw)

Papers by FIDEL CRUZ PEREGRINO

In this paper, we present the classical Bondi accretion theory for the case of non-isothermal acc... more In this paper, we present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disk as the emitter of UV photons and a spherical central object as a source of X-ray emission. In the present analysis, the UV emission from the accretion disk is assumed to have an angular dependence, while the X-ray/central object radiation is assumed to be isotropic. This allows us to build streamlines in any angular direction we need to. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion d...

Revista Mexicana De Astronomia Y Astrofisica, 2009

We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observ... more We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observations show that this source is a system of three galaxies. Two galaxies (A and B), which are separated in projection ≈ 10 kpc, show some evidence of tidal interaction between them. The spiral-like Galaxy B presents a disk-wide H emission and a high infrared luminosity, from near to mid-infrared wavelengths. We suggest that such luminosity is due to a probable disk-wide star-burst triggered by the ongoing gravitational interaction with Galaxy A. Galaxy B can be classi ed as a Luminous Infrared Galaxy (LIRG). We estimate that a binary merger in the system is likely to occur in < 1 Gyr. It is probable that this IRAS source will harbor in the future an Ultra LIRG, according to the evolutionary scheme of Sanders & Mirabel (1996).

arXiv: Astrophysics, 2001

We present the results of N-body simulations of the accretion of high-density dwarf galaxies by l... more We present the results of N-body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the ratio of galaxy masses is 3:1. The cusp of the dwarf galaxy is always disrupted during the merger, leading to a remnant with a weak power law in the intrinsic density and a ``core'' in the projected density. Removing both black holes from the giant and dwarf galaxies allows the dwarf galaxy to remain intact and leads to a remnant with a high central density, contrary to what is observed. Our results support the hypothesis than the persistence of low-density cores in giant galaxies following mergers is a consequence of the existence of supermassive central black holes.

Applied Mathematics and Computation

In this paper, the consistency of the smoothed particle hydrodynamics (SPH) interpolation formula... more In this paper, the consistency of the smoothed particle hydrodynamics (SPH) interpolation formula is investigated by analytical means. A novel error analysis is developed in n-dimensional space using the Poisson summation formula, which enables the simultaneous treatment of both the kernel and particle approximation errors for arbitrary particle distributions. New consistency integral relations are derived for the particle approximation, which correspond to the cosine Fourier transform of the kernel consistency conditions. The functional dependence of the error bounds on the SPH interpolation parameters, namely the smoothing length, h, and the number of particles within the kernel support, N , is demonstrated explicitly from which consistency conditions arise. As N → ∞, the particle approximation converges to the kernel approximation independently of h provided that the particle mass scales with h as m ∝ h β with β > n, where n is the spatial dimension. This implies that as h → 0, the joint limit m → 0, N → ∞, and N → ∞ is necessary for complete convergence to the continuum, where N is the total number of particles. The analysis also reveals a dominant error term of the form (ln N ) n /N for finite N , as it has long been conjectured based on the similarity between the SPH and the quasi-Monte Carlo estimates. When N ≫ 1, the error of the SPH interpolant decays as N −1 independently of the dimension. This ensures approximate partition of unity of the kernel volume.

The Astrophysical Journal

The Astrophysical Journal, 2017

The Astrophysical Journal Supplement Series, 2016

We present digital tables for the radiative terms that appear in the energy and momentum equation... more We present digital tables for the radiative terms that appear in the energy and momentum equations used to simulate the accretion onto supermassive black holes (SMBHs) in the center of galaxies. Cooling and heating rates and radiative accelerations are calculated with two different Spectral Energy Distributions (SEDs). One SED is composed of an accretion disk + [X-ray]-powerlaw, while the other is made of an accretion disk + [Corona]-bremsstrahlung with T X = 1.16 × 10 8 K, where precomputed conditions of adiabatic expansion are included. Quantification of different physical mechanisms at operation are presented, showing discrepancies and similarities between both SEDs in different ranges of fundamental physical parameters (i.e., ionization parameter, density, and temperature). With the recent discovery of outflows originating at sub-parsec scales, these tables may provide a useful tool to model gas accretion processes onto a SMBH.

Perspectives on Global Development and Technology, 2016

Human development has been based on the use of the energy resources, especially those of fossil o... more Human development has been based on the use of the energy resources, especially those of fossil origin (oil, gas, coal, etc.), which are not infinite and damage ecosystems; it is of paramount importance to make a transition to other alternative sources of energy. We compare and discuss many global sources of energy and their impact, based on the useful parameter called energy returned on energy invested or energy return on investment (eroi). In the long run we could expect renewed emphasis on enhanced (stimulated or hot dry rock) geothermal energy sources due to technological advances in deep drilling and the availability of this kind of energy 365 days per year and 24 hours of a day.

Revista mexicana de astronomía y astrofísica

We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observ... more We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observations show that this source is a system of three galax- ies. Two galaxies (A and B), which are separated in projection =10 kpc, show some evidence of tidal interaction between them. The spiral-like Galaxy B presents a disk-wide Hf emission and a high infrared luminosity, from near to mid-infrared wavelengths. We suggest that such luminosity is due to a probable disk-wide star-burst triggered by the ongoing gravitational interaction with Galaxy A. Galaxy B can be classified as a Luminous Infrared Galaxy (LIRG). We estimate that a bi nary merger in the system is likely to occur in lt; 1 Gyr. It is probable that this IRAS source will harbor in the future an Ultra LIRG, according to the evolutionary scheme of Sanders & Mirabel (1996).

We present the results of N -body simulations of the accretion of high-density dwarf galaxies by ... more We present the results of N -body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the ratio of galaxy masses is 3 : 1. The cusp of the dwarf galaxy is always disrupted during the merger, leading to a remnant with a weak power law in the intrinsic density and a "core" in the projected density. Removing both black holes from the giant and dwarf galaxies allows the dwarf galaxy to remain intact and leads to a remnant with a high central density, contrary to what is observed. Our results support the hypothesis than the persistence of low-density cores in giant galaxies following mergers is a consequence of the existence of supermassive central black holes.

The Astrophysical Journal, 2001

We simulate the accretion of high-density dwarf galaxies by low-density giant galaxies, using mod... more We simulate the accretion of high-density dwarf galaxies by low-density giant galaxies, using models that contain both power-law central density cusps and central point masses representing supermassive black holes. The final density profiles of the merger remnants are always similar to the initial density profile of the giant galaxy, for two reasons. 1. The density of the dwarf galaxy is reduced by impulsive heating whenever it passes near the black hole of the giant galaxy. 2. The central density of the giant galaxy drops as it absorbs orbital energy from the dwarf galaxy. The presence or absence of a black hole in the dwarf galaxy has little effect on the final density profile. Our results suggest that the accretion of dense satellites need not result in merger remnants with high central densities.

The Astrophysical Journal, 2009

We determine both representations of the Fundamental Plane [R e ∝ σ a 0 I −b e andR e ∝ (σ 2 0 I ... more We determine both representations of the Fundamental Plane [R e ∝ σ a 0 I −b e andR e ∝ (σ 2 0 I −1 e ) λ ] and the luminosity-effective phase space density (L ∝ f −γ e ) scaling relation for N -body remnants of binary mergers of spiral-like galaxies. The main set of merger simulations involves a mass-ratio of the progenitors in the range of about 1:1 to 1:5, harboring or not a bulge-like component, and are constructed using a cosmological motivated model. Equal-mass mergers are also considered. Remnants lead to average values for the scaling indices of a ≈ 1.6, b ≈ 0.6, λ ≈ 0.7, and γ ≈ 0.65. These values are consistent with those of K-band observations ) of ellipticals: a ≈ 1.5, b ≈ 0.8, λ ≈ 0.7, and γ ≈ 0.60. The b index is, however, not well reproduced. This study does not allow us to establish a conclusive preference for models with or without a bulge as progenitors. Our results indicate that the L-f e and FP scalings might be determined to a large extent by dissipationless processes, a result that appears to be in contradiction to other dissipationless results.

The Astrophysical Journal, 2004

The Astrophysical Journal, 612:593-596, 2004 September 10 © 2004. The American Astronomical Socie... more The Astrophysical Journal, 612:593-596, 2004 September 10 © 2004. The American Astronomical Society. All rights reserved. Printed in USA. Formation of Cuspy Density Profiles through Gravitational Cold Collapses around a Central Supermassive Black Hole. ...

Monthly Notices of the Royal Astronomical Society, 2006

Sérsic parameters characterising the density profiles of remnants formed in collision-less disc g... more Sérsic parameters characterising the density profiles of remnants formed in collision-less disc galaxy mergers are obtained; no bulge is included in our simulations. For the luminous component we find that the Sérsic index is n ∈ (1.5, 5.3) with n ≈ 3 ± 1 and an effective radius of R e ∈ (1.6, 12.9) kpc with R e ≈ 5 ± 3 kpc. The mean values of these quantities increases as the radial interval of fitting is reduced. A strong correlation of n with the central projected density I 0 is found (n ∝ I −0.14 0

Revista Mexicana de Astronomıa y …, 2007

... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Naciona... more ... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Nacional Autónoma de México, Apdo ... Aguilar, LA, & Merritt, D. 1990, ApJ, 354, 33 Bender, R. 1988, A&A, 74, 385 Binney, J., & Merrifield, M. 1998, Galactic Astronomy (Princenton: Princenton ...

Revista Mexicana de Astronomıa y …, 2007

... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Naciona... more ... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Nacional Autónoma de México, Apdo ... Aguilar, LA, & Merritt, D. 1990, ApJ, 354, 33 Bender, R. 1988, A&A, 74, 385 Binney, J., & Merrifield, M. 1998, Galactic Astronomy (Princenton: Princenton ...

In this paper, we present the classical Bondi accretion theory for the case of non-isothermal acc... more In this paper, we present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disk as the emitter of UV photons and a spherical central object as a source of X-ray emission. In the present analysis, the UV emission from the accretion disk is assumed to have an angular dependence, while the X-ray/central object radiation is assumed to be isotropic. This allows us to build streamlines in any angular direction we need to. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion d...

Revista Mexicana De Astronomia Y Astrofisica, 2009

We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observ... more We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observations show that this source is a system of three galaxies. Two galaxies (A and B), which are separated in projection ≈ 10 kpc, show some evidence of tidal interaction between them. The spiral-like Galaxy B presents a disk-wide H emission and a high infrared luminosity, from near to mid-infrared wavelengths. We suggest that such luminosity is due to a probable disk-wide star-burst triggered by the ongoing gravitational interaction with Galaxy A. Galaxy B can be classi ed as a Luminous Infrared Galaxy (LIRG). We estimate that a binary merger in the system is likely to occur in < 1 Gyr. It is probable that this IRAS source will harbor in the future an Ultra LIRG, according to the evolutionary scheme of Sanders & Mirabel (1996).

arXiv: Astrophysics, 2001

We present the results of N-body simulations of the accretion of high-density dwarf galaxies by l... more We present the results of N-body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the ratio of galaxy masses is 3:1. The cusp of the dwarf galaxy is always disrupted during the merger, leading to a remnant with a weak power law in the intrinsic density and a ``core'' in the projected density. Removing both black holes from the giant and dwarf galaxies allows the dwarf galaxy to remain intact and leads to a remnant with a high central density, contrary to what is observed. Our results support the hypothesis than the persistence of low-density cores in giant galaxies following mergers is a consequence of the existence of supermassive central black holes.

Applied Mathematics and Computation

In this paper, the consistency of the smoothed particle hydrodynamics (SPH) interpolation formula... more In this paper, the consistency of the smoothed particle hydrodynamics (SPH) interpolation formula is investigated by analytical means. A novel error analysis is developed in n-dimensional space using the Poisson summation formula, which enables the simultaneous treatment of both the kernel and particle approximation errors for arbitrary particle distributions. New consistency integral relations are derived for the particle approximation, which correspond to the cosine Fourier transform of the kernel consistency conditions. The functional dependence of the error bounds on the SPH interpolation parameters, namely the smoothing length, h, and the number of particles within the kernel support, N , is demonstrated explicitly from which consistency conditions arise. As N → ∞, the particle approximation converges to the kernel approximation independently of h provided that the particle mass scales with h as m ∝ h β with β > n, where n is the spatial dimension. This implies that as h → 0, the joint limit m → 0, N → ∞, and N → ∞ is necessary for complete convergence to the continuum, where N is the total number of particles. The analysis also reveals a dominant error term of the form (ln N ) n /N for finite N , as it has long been conjectured based on the similarity between the SPH and the quasi-Monte Carlo estimates. When N ≫ 1, the error of the SPH interpolant decays as N −1 independently of the dimension. This ensures approximate partition of unity of the kernel volume.

The Astrophysical Journal

The Astrophysical Journal, 2017

The Astrophysical Journal Supplement Series, 2016

We present digital tables for the radiative terms that appear in the energy and momentum equation... more We present digital tables for the radiative terms that appear in the energy and momentum equations used to simulate the accretion onto supermassive black holes (SMBHs) in the center of galaxies. Cooling and heating rates and radiative accelerations are calculated with two different Spectral Energy Distributions (SEDs). One SED is composed of an accretion disk + [X-ray]-powerlaw, while the other is made of an accretion disk + [Corona]-bremsstrahlung with T X = 1.16 × 10 8 K, where precomputed conditions of adiabatic expansion are included. Quantification of different physical mechanisms at operation are presented, showing discrepancies and similarities between both SEDs in different ranges of fundamental physical parameters (i.e., ionization parameter, density, and temperature). With the recent discovery of outflows originating at sub-parsec scales, these tables may provide a useful tool to model gas accretion processes onto a SMBH.

Perspectives on Global Development and Technology, 2016

Human development has been based on the use of the energy resources, especially those of fossil o... more Human development has been based on the use of the energy resources, especially those of fossil origin (oil, gas, coal, etc.), which are not infinite and damage ecosystems; it is of paramount importance to make a transition to other alternative sources of energy. We compare and discuss many global sources of energy and their impact, based on the useful parameter called energy returned on energy invested or energy return on investment (eroi). In the long run we could expect renewed emphasis on enhanced (stimulated or hot dry rock) geothermal energy sources due to technological advances in deep drilling and the availability of this kind of energy 365 days per year and 24 hours of a day.

Revista mexicana de astronomía y astrofísica

We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observ... more We report optical and near-infrared imaging and photometry for the IRAS 02290+2533 source. Observations show that this source is a system of three galax- ies. Two galaxies (A and B), which are separated in projection =10 kpc, show some evidence of tidal interaction between them. The spiral-like Galaxy B presents a disk-wide Hf emission and a high infrared luminosity, from near to mid-infrared wavelengths. We suggest that such luminosity is due to a probable disk-wide star-burst triggered by the ongoing gravitational interaction with Galaxy A. Galaxy B can be classified as a Luminous Infrared Galaxy (LIRG). We estimate that a bi nary merger in the system is likely to occur in lt; 1 Gyr. It is probable that this IRAS source will harbor in the future an Ultra LIRG, according to the evolutionary scheme of Sanders & Mirabel (1996).

We present the results of N -body simulations of the accretion of high-density dwarf galaxies by ... more We present the results of N -body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the ratio of galaxy masses is 3 : 1. The cusp of the dwarf galaxy is always disrupted during the merger, leading to a remnant with a weak power law in the intrinsic density and a "core" in the projected density. Removing both black holes from the giant and dwarf galaxies allows the dwarf galaxy to remain intact and leads to a remnant with a high central density, contrary to what is observed. Our results support the hypothesis than the persistence of low-density cores in giant galaxies following mergers is a consequence of the existence of supermassive central black holes.

The Astrophysical Journal, 2001

We simulate the accretion of high-density dwarf galaxies by low-density giant galaxies, using mod... more We simulate the accretion of high-density dwarf galaxies by low-density giant galaxies, using models that contain both power-law central density cusps and central point masses representing supermassive black holes. The final density profiles of the merger remnants are always similar to the initial density profile of the giant galaxy, for two reasons. 1. The density of the dwarf galaxy is reduced by impulsive heating whenever it passes near the black hole of the giant galaxy. 2. The central density of the giant galaxy drops as it absorbs orbital energy from the dwarf galaxy. The presence or absence of a black hole in the dwarf galaxy has little effect on the final density profile. Our results suggest that the accretion of dense satellites need not result in merger remnants with high central densities.

The Astrophysical Journal, 2009

We determine both representations of the Fundamental Plane [R e ∝ σ a 0 I −b e andR e ∝ (σ 2 0 I ... more We determine both representations of the Fundamental Plane [R e ∝ σ a 0 I −b e andR e ∝ (σ 2 0 I −1 e ) λ ] and the luminosity-effective phase space density (L ∝ f −γ e ) scaling relation for N -body remnants of binary mergers of spiral-like galaxies. The main set of merger simulations involves a mass-ratio of the progenitors in the range of about 1:1 to 1:5, harboring or not a bulge-like component, and are constructed using a cosmological motivated model. Equal-mass mergers are also considered. Remnants lead to average values for the scaling indices of a ≈ 1.6, b ≈ 0.6, λ ≈ 0.7, and γ ≈ 0.65. These values are consistent with those of K-band observations ) of ellipticals: a ≈ 1.5, b ≈ 0.8, λ ≈ 0.7, and γ ≈ 0.60. The b index is, however, not well reproduced. This study does not allow us to establish a conclusive preference for models with or without a bulge as progenitors. Our results indicate that the L-f e and FP scalings might be determined to a large extent by dissipationless processes, a result that appears to be in contradiction to other dissipationless results.

The Astrophysical Journal, 2004

The Astrophysical Journal, 612:593-596, 2004 September 10 © 2004. The American Astronomical Socie... more The Astrophysical Journal, 612:593-596, 2004 September 10 © 2004. The American Astronomical Society. All rights reserved. Printed in USA. Formation of Cuspy Density Profiles through Gravitational Cold Collapses around a Central Supermassive Black Hole. ...

Monthly Notices of the Royal Astronomical Society, 2006

Sérsic parameters characterising the density profiles of remnants formed in collision-less disc g... more Sérsic parameters characterising the density profiles of remnants formed in collision-less disc galaxy mergers are obtained; no bulge is included in our simulations. For the luminous component we find that the Sérsic index is n ∈ (1.5, 5.3) with n ≈ 3 ± 1 and an effective radius of R e ∈ (1.6, 12.9) kpc with R e ≈ 5 ± 3 kpc. The mean values of these quantities increases as the radial interval of fitting is reduced. A strong correlation of n with the central projected density I 0 is found (n ∝ I −0.14 0

Revista Mexicana de Astronomıa y …, 2007

... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Naciona... more ... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Nacional Autónoma de México, Apdo ... Aguilar, LA, & Merritt, D. 1990, ApJ, 354, 33 Bender, R. 1988, A&A, 74, 385 Binney, J., & Merrifield, M. 1998, Galactic Astronomy (Princenton: Princenton ...

Revista Mexicana de Astronomıa y …, 2007

... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Naciona... more ... Héctor Aceves, Fidel Cruz, and Héctor Velázquez: Instituto de Astronomıa, Universidad Nacional Autónoma de México, Apdo ... Aguilar, LA, & Merritt, D. 1990, ApJ, 354, 33 Bender, R. 1988, A&A, 74, 385 Binney, J., & Merrifield, M. 1998, Galactic Astronomy (Princenton: Princenton ...