J. A. Surace

Publications (79)119.68 Total impact

• Article: Mid-Infrared Properties of Nearby Luminous Infrared Galaxies I: Spitzer IRS Spectra for the GOALS Sample

  S. Stierwalt, L. Armus, J. A. Surace, H. Inami, A. O. Petric, T. Diaz-Santos, S. Haan, V. Charmandaris, J. Howell, D. C. Kim, [......], S. Lord, B. F. Madore, J. E. Melbourne, E. J. Murphy, J. A. Rich, B. Schulz, E. Sturm, V. U, T. Vavilkin, K. Xu
  [show abstract] [hide abstract]
  ABSTRACT: The Great Observatories All-Sky LIRG Survey (GOALS) is a multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer spectra covering 5-38um and provide a basic analysis of the mid-IR spectral properties for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra. The GOALS sample of 244 nuclei in 180 luminous and 22 ultraluminous IR galaxies represents a complete subset of the IRAS RBGS and covers a range of merger stages, morphologies and spectral types. The majority (>60%) of GOALS LIRGs have high 6.2um PAH equivalent widths (EQW > 0.4um) and low levels of silicate absorption (s_9.7um >-1.0). There is a general trend among the U/LIRGs for silicate depth and MIR slope to increase with LIR. U/LIRGs in the late stages of a merger also have on average steeper MIR slopes and higher levels of dust obscuration. Together these trends suggest that as gas & dust is funneled towards the center of a coalescing merger, the nuclei become more compact and obscured. The sources that depart from these correlations have very low PAH EQW (EQW < 0.1um) consistent with their MIR emission being dominated by an AGN. The most heavily dust obscured sources are the most compact in their MIR emission, suggesting that the obscuring (cool) dust is associated with the outer regions of the starburst. As the merger progresses a marked decline is seen for the fraction of high EQW (star formation dominated) sources while the fraction of composite sources increases but the fraction of AGN-dominated sources remains low. When compared to the MIR spectra of submillimeter galaxies (SMGs) at z~2, the average GOALS LIRG is more absorbed at 9.7um and has more PAH emission. However, when the AGN contributions to both the local LIRGs and the high-z SMGs are removed, the average local starbursting LIRG closely resembles the starbursting SMGs.
  02/2013;
• Article: The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals (PASP, 124, 714, [2012])

  J -C Mauduit, M Lacy, D Farrah, J ~A Surace, M Jarvis, S Oliver, C Maraston, M Vaccari, L Marchetti, G Zeimann, [......], C ~J Simpson, I Smail, G ~K Squires, J ~A Stevens, R Taylor, M Trichas, T Urrutia, E Kampen, A Verma, C ~K Xu
  pasp. 10/2012; 124:1135-1136.
• Conference Proceeding: Modifications to the warm Spitzer data reduction pipeline

  P ~J Lowrance, S ~J Carey, J ~E Krick, J ~A Surace, W ~J Glaccum, I Khan, J ~G Ingalls, S Laine, C Grillmair
  Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 09/2012
• Article: Investigation of Dual Active Nuclei, Outflows, Shock-Heated Gas, and Young Star Clusters in Markarian 266

  J. M. Mazzarella, K. Iwasawa, T. Vavilkin, L. Armus, D. -C. Kim, G. Bothun, A. S. Evans, H. W. W. Spoon, S. Haan, J. H. Howell, [......], P. Appleton, B. H. P. Chan, D. T. Frayer, H. Inami, E. Ye. Khachikian, B. F. Madore, G. C. Privon, E. Sturm, Vivian U, S. Veilleux
  [show abstract] [hide abstract]
  ABSTRACT: Results of observations with the Spitzer, Hubble, GALEX, Chandra, and XMM-Newton space telescopes are presented for the Luminous Infrared Galaxy (LIRG) merger Mrk 266. The SW (Seyfert 2) and NE (LINER) nuclei reside in galaxies with Hubble types SBb (pec) and S0/a (pec), respectively. Both galaxies have L > L*, and they are inferred to each contain a ~2.5x10^8 M_sun black hole. Mrk 266 SW is likely the primary source of a bright Fe K-alpha line detected from the system, consistent with the reflection-dominated X-ray spectrum of a heavily obscured AGN. Optical knots embedded in an arc with aligned radio continuum radiation, combined with luminous H_2 line emission, provide evidence for a radiative bow shock in an AGN-driven outflow surrounding the NE nucleus. Soft X-ray emission modeled as shock-heated plasma is co-spatial with radio continuum emission between the galaxies. Mid-IR diagnostics indicate roughly equal contributions of AGN and starburst radiation powering the bolometric luminosity. Approximately 120 star clusters have been detected, with most having estimated ages < 50 Myr. Detection of 24 micron emission extending ~34 arcsec (20 kpc) north of the galaxies is interpreted as ~2x10^7 M_sun of dust entrained in an outflowing superwind; at optical wavelengths this region is resolved into a fragmented morphology indicative of Rayleigh-Taylor instabilities in an expanding shell of ionized gas. Mrk 266 demonstrates that the dust "blow-out" phase can begin in a LIRG well before the galaxies fully coalesce during a subsequent ULIRG phase, and rapid gas consumption in luminous dual AGNs (kpc scale separations) early in the merger process may explain the paucity of detected binary QSOs (sub-pc scale orbits) in large surveys. An evolutionary sequence is proposed representing a progression from dual to binary AGNs, accompanied by an increase in observed L_x/L_ir ratios by 10^4 or more.
  08/2012;
• Article: The Spitzer Extragalactic Representative Volume Survey (SERVS): survey definition and goals

  J. -C. Mauduit, M. Lacy, D. Farrah, J. A. Surace, M. Jarvis, S. Oliver, C. Maraston, M. Vaccari, L. Marchetti, G. Zeimann, [......], C. J. Simpson, I. Smail, G. K. Squires, J. A. Stevens, R. Taylor, M. Trichas, T. Urrutia, E. van Kampen, A. Verma, C. K. Xu
  [show abstract] [hide abstract]
  ABSTRACT: We present the Spitzer Extragalactic Representative Volume Survey (SERVS), an 18 square degrees medium-deep survey at 3.6 and 4.5 microns with the post-cryogenic Spitzer Space Telescope to ~2 microJy (AB=23.1) depth of five highly observed astronomical fields (ELAIS-N1, ELAIS-S1, Lockman Hole, Chandra Deep Field South and XMM-LSS). SERVS is designed to enable the study of galaxy evolution as a function of environment from z~5 to the present day, and is the first extragalactic survey both large enough and deep enough to put rare objects such as luminous quasars and galaxy clusters at z>1 into their cosmological context. SERVS is designed to overlap with several key surveys at optical, near- through far-infrared, submillimeter and radio wavelengths to provide an unprecedented view of the formation and evolution of massive galaxies. In this paper, we discuss the SERVS survey design, the data processing flow from image reduction and mosaicing to catalogs, as well as coverage of ancillary data from other surveys in the SERVS fields. We also highlight a variety of early science results from the survey.
  06/2012;
• Article: Two Distant Halo Velocity Groups Discovered by the Palomar Transient Factory

  B. Sesar, J. G. Cohen, D. Levitan, C. J. Grillmair, M. Juric, E. N. Kirby, R. R. Laher, E. O. Ofek, J. A. Surace, S. R. Kulkarni, T. A. Prince
  [show abstract] [hide abstract]
  ABSTRACT: We report the discovery of two new halo velocity groups (Cancer groups A and B) traced by 8 distant RR Lyrae stars and observed by the Palomar Transient Factory (PTF) survey at R.A.~129 deg, Dec~20 deg (l~205 deg, b~32 deg). Located at 92 kpc from the Galactic center (86 kpc from the Sun), these are some of the most distant substructures in the Galactic halo known to date. Follow-up spectroscopic observations with the Palomar Observatory 5.1-m Hale telescope and W. M. Keck Observatory 10-m Keck I telescope indicate that the two groups are moving away from the Galaxy at v_{gsr} = 78.0+-5.6 km/s (Cancer group A) and v_{gsr} = 16.3+-7.1 km/s (Cancer group B). The groups have velocity dispersions of \sigma_{v_{gsr}}=12.4+-5.0 km/s and \sigma_{v_{gsr}}=14.9+-6.2 km/s, and are spatially extended (about several kpc) making it very unlikely that they are bound systems, and are more likely to be debris of tidally disrupted dwarf galaxies or globular clusters. Both groups are metal-poor (median metallicities of [Fe/H] = -1.6 dex and [Fe/H] =-2.1 dex), and have a somewhat uncertain (due to small sample size) metallicity dispersion of ~0.4 dex, suggesting dwarf galaxies as progenitors. Two additional RR Lyrae stars with velocities consistent with those of the Cancer groups have been observed ~25 deg east, suggesting possible extension of the groups in that direction.
  06/2012;
• Source

  Available from: ArXiv

  Article: Multi-wavelength GOALS Observations of Star Formation and Active Galactic Nucleus Activity in the Luminous Infrared Galaxy IC 883

  F. Modica, T. Vavilkin, A. S. Evans, D. -C. Kim, J. M. Mazzarella, K. Iwasawa, A. Petric, J. H. Howell, J. A. Surace, L. Armus, H. W. W. Spoon, D. B. Sanders, J. E. Barnes
  [show abstract] [hide abstract]
  ABSTRACT: New optical HST, Spitzer, GALEX, and Chandra observations of the single-nucleus, luminous infrared galaxy (LIRG) merger IC 883 are presented. The galaxy is a member of the Great Observatories All-sky LIRG Survey (GOALS), and is of particular interest for a detailed examination of a luminous late-stage merger due to the richness of the optically-visible star clusters and the extended nature of the nuclear X-ray, mid-IR, CO and radio emission. In the HST ACS images, the galaxy is shown to contain 156 optically visible star clusters distributed throughout the nuclear regions and tidal tails of the merger, with a majority of visible clusters residing in an arc ~ 3-7 kpc from the position of the mid-infrared core of the galaxy. The luminosity functions of the clusters have an alpha_F435W ~ -2.17+/-0.22 and alpha_F814W ~ -2.01+/-0.21. Further, the colors and absolute magnitudes of the majority of the clusters are consistent with instantaneous burst population synthesis model ages in the range of a few x10^7 - 10^8 yrs (for 10^5 M_sun clusters), but may be as low as few x10^6 yrs with extinction factored in. The X-ray and mid-IR spectroscopy are indicative of predominantly starburst-produced nuclear emission, and the star formation rate is ~ 80 M_sun / yr. The kinematics of the CO emission and the morphology of both the CO and radio emission are consistent with the nuclear starburst being situated in a highly inclined disk 2 kpc in diameter with an infrared surface brightness mu_IR ~ 2x10^11 L_sun kpc^-2, a factor of 10 less than that of the Orion star-forming region. Finally, the detection of the [Ne V] 14.32 um emission line is evidence that an AGN is present. The faintness of the line (i.e., [Ne V] / [Ne II] um ~ 0.01) and the small equivalent width of the 6.2 um PAH feature ($= 0.39\mu$m) are both indicative of a relatively weak AGN. (abridged)
  11/2011;
• Source

  Available from: Vassilis Charmandaris

  Article: Spitzer IRS Spectral Mapping of the Toomre Sequence: Spatial Variations of PAH, Gas, and Dust Properties in Nearby Major Mergers

  S. Haan, L. Armus, S. Laine, V. Charmandaris, J. D. Smith, F. Schweizer, B Brandl, A. S. Evans, J. A. Surace, T. Diaz-Santos, P. Beirao, E. J. Murphy, S. Stierwalt, J. E. Hibbard, M. Yun, T. H. Jarrett
  [show abstract] [hide abstract]
  ABSTRACT: We have mapped the key mid-IR diagnostics in eight major merger systems of the Toomre Sequence (NGC4676, NGC7592, NGC6621, NGC2623, NGC6240, NGC520, NGC3921, and NGC7252) using the Spitzer Infrared Spectrograph (IRS). With these maps, we explore the variation of the ionized-gas, PAH, and warm-gas (H_2) properties across the sequence and within the galaxies. While the global PAH interband strength and ionized gas flux ratios ([Ne III]/[Ne II]) are similar to those of normal star forming galaxies, the distribution of the spatially resolved PAH and fine structure line flux ratios is significant different from one system to the other. Rather than a constant H_2/PAH flux ratio, we find that the relation between the H_2 and PAH fluxes is characterized by a power law with a roughly constant exponent (0.61+/-0.05) over all merger components and spatial scales. While following the same power law on local scales, three galaxies have a factor of ten larger integrated (i.e. global) H_2/PAH flux ratio than the rest of the sample, even larger than what it is in most nearby AGNs. These findings suggest a common dominant excitation mechanism for H_2 emission over a large range of global H_2/PAH flux ratios in major mergers. Early merger systems show a different distribution between the cold (CO J=1-0) and warm (H_2) molecular gas component, which is likely due to the merger interaction. Strong evidence for buried star formation in the overlap region of the merging galaxies is found in two merger systems (NGC6621 and NGC7592) as seen in the PAH, [Ne II], [Ne III], and warm gas line emission, but with no apparent corresponding CO (J=1-0) emission. Our findings also demonstrate that the variations of the physical conditions within a merger are much larger than any systematic trends along the Toomre Sequence.
  10/2011;
• Source

  Available from: ArXiv

  Article: C-GOALS: Chandra observations of a complete sample of luminous infrared galaxies from the IRAS Revised Bright Galaxy Survey

  K. Iwasawa, D. B. Sanders, Stacy H. Teng, Vivian U, L. Armus, A. S. Evans, J. H. Howell, S. Komossa, J. M. Mazzarella, A. O. Petric, J. A. Surace, T. Vavilkin, S. Veilleux, N. Trentham
  [show abstract] [hide abstract]
  ABSTRACT: We present X-ray data for a complete sample of 44 luminous infrared galaxies (LIRGs), obtained with the Chandra X-ray Observatory. These are the X-ray observations of the high luminosity portion of the Great Observatory All-sky LIRG Survey (GOALS), which includes the most luminous infrared selected galaxies, log (Lir/Lsun) > 11.73, in the local universe, z < 0.088. X-rays were detected from 43 out of 44 objects, and their arcsec-resolution images, spectra, and radial brightness distributions are presented. With a selection by hard X-ray colour and the 6.4 keV iron line, AGN are found in 37% of the objects, with higher luminosity sources more likely to contain an AGN. These AGN also tend to be found in late-stage mergers. The AGN fraction would increase to 48% if objects with mid-IR [Ne V] detection are included. Double AGN are clearly detected only in NGC 6240 among 24 double/triple systems. Other AGN are found either in single nucleus objects or in one of the double nuclei at similar rates. Objects without conventional X-ray signatures of AGN appear to be hard X-ray quiet, relative to the X-ray to far-IR correlation for starburst galaxies, as discussed elsewhere. Most objects also show extended soft X-ray emission, which is likely related to an outflow from the nuclear region, with a metal abundance pattern suggesting enrichment by core collapse supernovae, as expected for a starburst.
  03/2011;
• Source

  Available from: Vassilis Charmandaris

  Article: Mid-Infrared Spectral Diagnostics of Luminous Infrared Galaxies

  A. O. Petric, L. Armus, J. Howell, B. Chan, J. M. Mazzarella, A. S. Evans, J. A. Surace, D. Sanders, P. Appleton, V. Charmandaris, [......], K. Iwasawa, D. Kim, B. Madore, J. Marshall, H. Spoon, S. Stierwalt, E. Sturm, V. U, T. Vavilkin, and S. Veilleux
  [show abstract] [hide abstract]
  ABSTRACT: We present a statistical analysis of the mid-infrared (MIR) spectra of 248 luminous infrared (IR) galaxies (LIRGs) which comprise the Great Observatories All-sky LIRG Survey (GOALS) observed with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. The GOALS sample enables a direct measurement of the relative contributions of star formation and active galactic nuclei (AGNs) to the total IR emission from a large sample of local LIRGs. The AGN contribution to the MIR emission (f AGN) is estimated by employing several diagnostics based on the properties of the [Ne V], [O IV], and [Ne II] fine-structure gas emission lines, the 6.2 μm polycyclic aromatic hydrocarbon (PAH), and the shape of the MIR continuum. We find that 18% of all LIRGs contain an AGN and that in 10% of all sources the AGN contributes more than 50% of the total IR luminosity. Summing up the total IR luminosity contributed by AGNs in all our sources suggests that AGNs supply ~12% of the total energy emitted by LIRGs. The average spectrum of sources with an AGN looks similar to the average spectrum of sources without an AGN, but it has lower PAH emission and a flatter MIR continuum. AGN-dominated LIRGs have higher IR luminosities, warmer MIR colors, and are found in interacting systems more often than pure starburst LIRGs. However, we find no linear correlations between these properties and f AGN. We used the IRAC colors of LIRGs to confirm that finding AGNs on the basis of their MIR colors may miss ~40% of AGN-dominated (U)LIRGs.
  The Astrophysical Journal 02/2011; 730(1):28. · 6.02 Impact Factor
• Article: The Nuclear Structure in Nearby Luminous Infrared Galaxies: Hubble Space Telescope NICMOS Imaging of the GOALS Sample

  S. Haan, J. A. Surace, L. Armus, A. S. Evans, J. H. Howell, J. M. Mazzarella, D. C. Kim, T. Vavilkin, H. Inami, D. B. Sanders, A. Petric, C. R. Bridge, J. L. Melbourne, V. Charmandaris, T. Diaz-Santos, E. J. Murphy, V. U, S. Stierwalt, and J. A. Marshall
  [show abstract] [hide abstract]
  ABSTRACT: We present results of Hubble Space Telescope (HST) NICMOS H-band imaging of 73 of the most luminous (i.e., log[L IR/L ☉]>11.4) infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. This data set combines multi-wavelength imaging and spectroscopic data from space-based (Spitzer, HST, GALEX, and Chandra) and ground-based telescopes. In this paper, we use high-resolution near-infrared data to recover nuclear structure that is obscured by dust at optical wavelengths and measure the evolution in this structure along the merger sequence. A large fraction of all galaxies in our sample possess double nuclei (~63%) or show evidence for triple nuclei (~6%). Half of these double nuclei are not visible in the HST B-band images due to dust obscuration. The majority of interacting LIRGs have remaining merger timescales of 0.3-1.3 Gyr, based on the projected nuclear separations and the mass ratio of nuclei. We find that the bulge luminosity surface density L Bulge/R 2 Bulge increases significantly along the merger sequence (primarily due to a decrease of the bulge radius), while the bulge luminosity shows a small increase toward late merger stages. No significant increase of the bulge Sérsic index is found. LIRGs that show no interaction features have on average a significantly larger bulge luminosity, suggesting that non-merging LIRGs have larger bulge masses than merging LIRGs. This may be related to the flux-limited nature of the sample and the fact that mergers can significantly boost the IR luminosity of otherwise low luminosity galaxies. We find that the projected nuclear separation is significantly smaller for ULIRGs (median value of 1.2 kpc) than for LIRGs (median value of 6.7 kpc), suggesting that the LIRG phase appears earlier in mergers than the ULIRG phase.
  The Astronomical Journal 02/2011; 141(3):100. · 4.03 Impact Factor
• Source

  Available from: ArXiv

  Article: The location of an active nucleus and the soft X-ray shadowing by a tidal tail in the ULIRG Mrk 273

  K. Iwasawa, J. M. Mazzarella, J. A. Surace, D. B. Sanders, L. Armus, A. S. Evans, J. H. Howell, S. Komossa, A. O. Petric, S. H. Teng, Vivian U, S. Veilleux
  [show abstract] [hide abstract]
  ABSTRACT: Analysis of data from the Chandra X-ray Observatory for the double nucleus ULIRG Mrk 273 reveals an absorbed hard X-ray source coincident with the southwest nucleus, implying that this unresolved near infrared source is where an active nucleus resides while the northern nuclear region contains a powerful starburst which dominates the far infrared luminosity. There is evidence of a slight image extension in the 6-7 keV band, where a Fe K line is present, towards the northern nucleus. A large-scale, diffuse emission nebula detected in soft X-rays contains a dark lane that spatially coincides with a high surface-brightness tidal tail extending ~50 arcsec (40 kpc) to the south. The soft X-ray source is likely located behind the tidal tail which absorbs X-ray photons along the line of sight. The estimated column density of cold gas in the tidal tail responsible for shadowing the soft X-rays is nH >= 6e+21 cm-2, consistent with the tidal tail having an edge-on orientation.
  01/2011;
• Source

  Available from: Vassilis Charmandaris

  Article: The Nuclear Structure in Nearby Luminous Infrared Galaxies: HST NICMOS Imaging of the GOALS Sample

  S. Haan, J. A. Surace, L. Armus, A. S. Evans, J. H. Howell, J. M. Mazzarella, D. -C. Kim, T. Vavilkin, H. Inami, D. B. Sanders, A. Petric, C. R. Bridge, J. L. Melbourne, V. Charmandaris, T. Diaz-Santos, E. J. Murphy, V. U, S. Stierwalt, J. A. Marshall
  [show abstract] [hide abstract]
  ABSTRACT: We present results of Hubble Space Telescope NICMOS H-band imaging of 73 of most luminous (i.e., log[L_IR/L_0]>11.4) Infrared Galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey (GOALS). This dataset combines multi-wavelength imaging and spectroscopic data from space (Spitzer, HST, GALEX, and Chandra) and ground-based telescopes. In this paper we use the high-resolution near-infrared data to recover nuclear structure that is obscured by dust at optical wavelengths and measure the evolution in this structure along the merger sequence. A large fraction of all galaxies in our sample possess double nuclei (~63%) or show evidence for triple nuclei (~6%). Half of these double nuclei are not visible in the HST B-band images due to dust obscuration. The majority of interacting LIRGs have remaining merger timescales of 0.3 to 1.3 Gyrs, based on the projected nuclear separations and the mass ratio of nuclei. We find that the bulge luminosity surface density increases significantly along the merger sequence (primarily due to a decrease of the bulge radius), while the bulge luminosity shows a small increase towards late merger stages. No significant increase of the bulge Sersic index is found. LIRGs that show no interaction features have on average a significantly larger bulge luminosity, suggesting that non merging LIRGs have larger bulge masses than merging LIRGs. This may be related to the flux limited nature of the sample and the fact that mergers can significantly boost the IR luminosity of otherwise low luminosity galaxies. We find that the projected nuclear separation is significantly smaller for ULIRGs (median value of 1.2 kpc) than for LIRGs (mean value of 6.7 kpc), suggesting that the LIRG phase appears earlier in mergers than the ULIRG phase. Comment: Accepted for publication in AJ, 51 pages, 18 figures. For supplementary figures, see http://goals.ipac.caltech.edu/publications.html
  12/2010;
• Source

  Available from: ArXiv

  Article: Specific star formation and the relation to stellar mass from 0 < z < 2 as seen in the far‐infrared at 70 and 160 μm

  Seb Oliver, M. Frost, D. Farrah, E. Gonzalez-Solares, D. L. Shupe, B. Henriques, I. Roseboom, A. Alfonso-Luis, T. S. R. Babbedge, D. Frayer, C. Lencz, C. J. Lonsdale, F. Masci, D. Padgett, M. Polletta, M. Rowan-Robinson, B. Siana, H. E. Smith, J. A. Surace, M. Vaccari
  [show abstract] [hide abstract]
  ABSTRACT: We use the Spitzer Wide-area InfraRed Extragalactic Legacy Survey (SWIRE) to explore the specific star formation activity of galaxies and their evolution near the peak of the cosmic far-infrared (FIR) background at 70 and 160 μm. We use a stacking analysis to determine the mean FIR properties of well-defined subsets of galaxies at flux levels well below the FIR catalogue detection limits of SWIRE and other Spitzer surveys. We tabulate the contribution of different subsets of galaxies to the FIR background at 70 and 160 μm. These long wavelengths provide a good constraint on the bolometric obscured emission. The large area provides good constraints at low z and in finer redshift bins than previous work. At all redshifts we find that the specific FIR luminosity decreases with increasing mass, following a trend LFIR/M*∝Mβ* with β=−0.38 ± 0.14. This is a more continuous change than expected from the De Lucia & Blaizot semi-analytic model suggesting modifications to the feedback prescriptions. We see an increase in the specific FIR luminosity by about a factor of ∼100 from 0 < z < 2 and find that the specific FIR luminosity evolves as (1 +z)α with α= 4.4 ± 0.3 for galaxies with 10.5 < log10M*/M⊙≤ 12. This is considerably steeper than the De Lucia & Blaizot semi-analytic model (α∼ 2.5). When separating galaxies into early and late types on the basis of the optical/IR spectral energy distributions we find that the decrease in specific FIR luminosity with stellar mass is stronger in early-type galaxies (β∼−0.46), while late-type galaxies exhibit a flatter trend (β∼−0.15). The evolution is strong for both classes but stronger for the early-type galaxies. The early types show a trend of decreasing strength of evolution as we move from lower to higher masses while the evolution of the late-type galaxies has little dependence on stellar mass. We suggest that in late-type galaxies we are seeing a consistently declining specific star formation rate α= 3.36 ± 0.16 through a common phenomenon, for example, exhaustion of gas supply, i.e. not systematically dependent on the local properties of the galaxy.
  Monthly Notices of the Royal Astronomical Society 07/2010; 405(4):2279 - 2294. · 4.90 Impact Factor
• Source

  Available from: Vassilis Charmandaris

  Article: The Buried Starburst in the Interacting Galaxy II Zw 096 as Revealed by the Spitzer Space Telescope

  Hanae Inami, L. Armus, J. A. Surace, J. M. Mazzarella, A. S. Evans, D. B. Sanders, J. H. Howell, A. Petric, T. Vavilkin, K. Iwasawa, [......], J. A. Marshall, H. Matsuhara, J. E. Melbourne, J. Rich, B. Schulz, H. W. W. Spoon, E. Sturm, V. U, S. Veilleux, K Xu
  [show abstract] [hide abstract]
  ABSTRACT: An analysis of data from the Spitzer Space Telescope, Hubble Space Telescope, Chandra X-ray Observatory, and AKARI Infrared Astronomy Satellite is presented for the z=0.036 merging galaxy system II Zw 096 (CGCG 448-020). Because II Zw 096 has an infrared luminosity of log(L_IR/L_sun) = 11.94, it is classified as a Luminous Infrared Galaxy (LIRG), and was observed as part of the Great Observatories All-sky LIRG Survey (GOALS). The Spitzer data suggest that 80% of the total infrared luminosity comes from an extremely compact, red source not associated with the nuclei of the merging galaxies. The Spitzer mid-infrared spectra indicate no high-ionization lines from a buried active galactic nucleus in this source. The strong detection of the 3.3 micron and 6.2 micron PAH emission features in the AKARI and Spitzer spectra also implies that the energy source of II Zw 096 is a starburst. Based on Spitzer infrared imaging and AKARI near-infrared spectroscopy, the star formation rate is estimated to be 120 M_sun/yr and > 45 M_sun/yr, respectively. Finally, the high-resolution B, I, and H-band images show many star clusters in the interacting system. The colors of these clusters suggest at least two populations - one with an age of 1-5 Myr and one with an age of 20-500 Myr, reddened by 0-2 magnitudes of visual extinction. The masses of these clusters span a range between 10^6-10^8 M_sun. This starburst source is reminiscent of the extra-nuclear starburst seen in NGC 4038/9 (the Antennae Galaxies) and Arp 299 but approximately an order of magnitude more luminous than the Antennae. The source is remarkable in that the off-nuclear infrared luminosity dominates the enitre system. Comment: 46 pages, 10 figures, accepted for publication in AJ
  04/2010;
• Conference Proceeding: Properties of Warm IRAC Data

  S ~J Carey, J ~A Surace, W ~J Glaccum, J Ingalls, J Krick, M Lacy, P Lowrance, S Laine, J O'Linger, J ~R Stauffer, S ~P Willner, J ~L Hora, W ~F Hoffmann, M ~L ~N Ashby, J Huang, M Marengo, M ~A Pahre, Z Wang, G ~G Fazio
  American Astronomical Society Meeting Abstracts #215; 01/2010
• Source

  Available from: M. Salvato

  Article: Spitzer 70 and 160 μm Observations of the COSMOS Field

  D. T. Frayer, D. B. Sanders, J. A. Surace, H. Aussel, M. Salvato, E. Le Floc'h, M. T. Huynh, N. Z. Scoville, A. Afonso-Luis, B. Bhattacharya, [......], J. S. Kartaltepe, A. M. Koekemoer, N. Lee, E. Murphy, M. T. Sargent, E. Schinnerer, K. Sheth, P. L. Shopbell, D. L. Shupe, and L. Yan
  [show abstract] [hide abstract]
  ABSTRACT: We present Spitzer 70 and 160 μm observations of the COSMOS Spitzer survey (S-COSMOS). The data processing techniques are discussed for the publicly released products consisting of images and source catalogs. We present accurate 70 and 160 μm source counts of the COSMOS field and find reasonable agreement with measurements in other fields and with model predictions. The previously reported counts for GOODS-North and the extragalactic First Look Survey are updated with the latest calibration, and counts are measured based on the large area SWIRE survey to constrain the bright source counts. We measure an extragalactic confusion noise level of σ c = 9.4 ± 3.3 mJy (q = 5) for the MIPS 160 μm band based on the deep S-COSMOS data and report an updated confusion noise level of σ c = 0.35 ± 0.15 mJy (q = 5) for the MIPS 70 μm band.
  The Astronomical Journal 09/2009; 138(5):1261. · 4.03 Impact Factor
• Source

  Available from: Joseph L. Hora

  Article: The IRAC Dark Field; Far- Infrared to X-ray Data

  J. E. Krick, J. A. Surace, D Thompson, M. L. N. Ashby, J. Hora, V. Gorjian, L Yan, D. T. Frayer, E. Egami, M. Lacy
  [show abstract] [hide abstract]
  ABSTRACT: We present 20 band photometry from the far-IR to X-ray in the Spitzer IRAC dark field. The bias for the near-IR camera on Spitzer is calibrated by observing a ~20 arcminute diameter "dark" field near the north ecliptic pole roughly every two-to-three weeks throughout the mission duration of Spitzer. The field is unique for its extreme depth, low background, high quality imaging, time-series information, and accompanying photometry including data taken with Akari, Palomar, MMT, KPNO, Hubble, and Chandra. This serendipitous survey contains the deepest mid-IR data taken to date. This dataset is well suited for studies of intermediate redshift galaxy clusters, high redshift galaxies, the first generation of stars, and the lowest mass brown dwarfs, among others. This paper provides a summary of the data characteristics and catalog generation from all bands collected to date as well as a discussion of photometric redshifts and initial and expected science results and goals. To illustrate the scientific potential of this unique dataset, we also present here IRAC color color diagrams. Comment: 12 pages, ApJS accepted
  09/2009;
• Source

  Available from: Joseph L. Hora

  Article: Galaxy Clusters in the IRAC Dark Field II: Mid-IR Sources

  J. E. Krick, J. A. Surace, D Thompson, M. L. N. Ashby, J. L. Hora, V. Gorjian, L Yan
  [show abstract] [hide abstract]
  ABSTRACT: We present infrared luminosities, star formation rates, colors, morphologies, locations, and AGN properties of 24 micron-detected sources in photometrically detected high-redshift clusters in order to understand the impact of environment on star formation and AGN evolution in cluster galaxies. We use three newly-identified z=1 clusters selected from the IRAC dark field; the deepest ever mid-IR survey with accompanying, 14 band multiwavelength data including deep HST imaging and deep wide-area Spitzer MIPS 24 micron imaging. We find 90 cluster members with MIPS detections within two virial radii of the cluster centers, of which 17 appear to have spectral energy distributions dominated by AGN and the rest dominated by star formation. We find that 43 of the star forming are luminous infrared galaxies (LIRGs). The majority of sources (81%) are spirals or irregulars. A large fraction (at least 25%) show obvious signs of interactions. The MIPS -detected member galaxies have varied spatial distributions as compared to the MIPS-undetected members with one of the three clusters showing SF galaxies being preferentially located on the cluster outskirts, while the other 2 clusters show no such trend. Both the AGN fraction and the summed SFR of cluster galaxies increases from z=0 to 1, at a rate that is a few times faster in clusters than over the same redshift range in the field. Cluster environment does have an effect on the evolution of both AGN fraction and SFR from redshift one to the present, but does not effect the infrared luminosities or morphologies of the MIPS sample. Star formation happens in the same way regardless of environment making MIPS sources look the same in the cluster and field, however the cluster environment does encourage a more rapid evolution with time as compared to the field. Comment: 18 pages, 9 figures, ApJ accepted
  05/2009;
• Conference Proceeding: Selection of Infrared-variable Objects in the IRAC Calibration Field

  M Fouesneau, M ~L ~N Ashby, J ~L Hora, J ~A Surace, J Krick
  American Astronomical Society Meeting Abstracts #214; 05/2009