Timothy Heckman

Interaction-induced star formation in a complete sample of 10^5 nearby star-forming galaxies (2007)

Li, Cheng, Kauffmann, Guinevere, Heckman, Timothy, Jing, Y. P., White, Simon D. M.

We investigate the clustering properties of a complete sample of 10^5 star-forming galaxies drawn from the SDSS DR4. On scales less than 100 kpc, the amplitude of the correlation function exhibits a...

Nitrogen Production in Starburst Galaxies Detected by GALEX (2007)

Mallery, Ryan P., Kewley, Lisa, Rich, R. Michael, Salim, Samir, Charlot, Stephane, Tremonti, Christy, ...

We investigate the production of nitrogen in star forming galaxies with ultraviolet (UV) radiation detected by the Galaxy Evolution Explorer Satellite (GALEX). We use a sample of 8,745 GALEX emission...

Emission-line Diagnostics of Low Metallicity AGN (2006)

Groves, Brent, Heckman, Timothy, Kauffmann, Guinevere

Current emission-line based estimates of the metallicity of active galactic nuclei (AGN) at both high and low redshifts indicate that AGN have predominantly solar to supersolar metallicities. This...

The formation of bulges and black holes: lessons from a census of active galaxies in the SDSS (2004)

Kauffmann, Guinevere, Heckman, Timothy

We examine the relationship between galaxies, supermassive black holes and AGN using a sample of 22,000 narrow-emission-line AGN drawn from a a sample of 122,000 galaxies from the Sloan Digital Sky...

Stellar Population in LLAGN.II: STIS observations (2004)

Delgado, Rosa M. Gonzalez, Fernandes, Roberto Cid, Perez, Enrique, Martins, Lucimara P., Storchi-Bergmann, Thaisa, Schmitt, Henrique, ...

We present a study of the stellar population in Low Luminosity AGN (LLAGN). Our goal is to search for spectroscopic signatures of young and intermediate age stars, and to investigate their...

Stellar Population in LLAGN.I: Ground-based observations (2004)

Fernandes, Roberto Cid, Delgado, Rosa M. Gonzalez, Schmitt, Henrique, Storchi-Bergmann, Thaisa, Martins, Lucimara P., Perez, Enrique, ...

(Abridge): We present a spectroscopic study of the stellar populations of Low Luminosity AGN (LLAGN). Our main goal is to determine whether the stars who live in the innermost (100 pc-scale) regions...

The Massive Stellar Content in the Starburst NGC3049: A Test for Hot-Star Mode (2002)

Delgado, Rosa M. Gonzalez, Leitherer, Claus, Stasinka, Grazyna, Heckman, Timothy

We have obtained high-spatial resolution ultraviolet and optical STIS spectroscopy and imaging of the metal-rich nuclear starburst in NGC3049. The stellar continuum and the absorption line spectrum...

Chandra Observations of the Evolving Core of the Starburst Galaxy NGC 253 (2002)

Weaver, Kimberly, Heckman, Timothy, Strickland, David, Dahlem, Michael

Chandra observations of the core of the nearby starburst galaxy NGC 253 reveal a heavily absorbed source of hard X-rays embedded within the nuclear starburst region. The source has an unabsorbed, 2...

Is a minor-merger driving the nuclear activity in the Seyfert 2 galaxy NGC 2110? (2002)

Delgado, Rosa M. Gonzalez, Arribas, Santiago, Perez, Enrique, Heckman, Timothy

We report on a detailed morphological and kinematic study of the isolated non-barred nearby Seyfert 2 galaxy NGC 2110. We combine Integral Field optical spectroscopy, with long-slit and WFPC2 imaging...

The Metal Content of Dwarf Starburst Winds: Results from Chandra Observations of NGC 1569 (2002)

Martin, Crystal, Kobulnicky, Henry, Heckman, Timothy

(Abridged) We present deep, Chandra spectral imaging of the dwarf starburst galaxy NGC 1569. The unprecedented spatial resolution allows us to spatially identify the components of the integrated \x...

Young and Intermediate Stellar population in Seyfert 2 galaxies (2000)

Delgado, Rosa M. Gonzalez, Heckman, Timothy, Leitherer, Claus

We present and discuss near-ultraviolet and optical ground-based spectra of the 20 brightest Seyfert 2 nuclei, and HST ultraviolet images and ultraviolet spectroscopy for a few of them. The goal is...

Synthetic spectra of H Balmer and HeI absorption lines. II: Evolutionary synthesis models for starburst and post-starburst galaxies (1999)

Delgado, Rosa M. Gonzalez, Leitherer, Claus, Heckman, Timothy

We present evolutionary stellar population synthesis models to predict the spectrum of a single-metallicity stellar population, with a spectral sampling of 0.3 A in five spectral regions between 3700...

The Role of Nuclear Starburst in Luminous Infrared Seyfert 2 Galaxies (1999)

Delgado, Rosa Gonzalez, Heckman, Timothy

We present HST (WFPC2 and FOC) images and UV GHRS spectra plus ground-based optical spectra of four Luminous Infrared Galaxies (LIRGs) that have Seyfert 2 nuclei (Mrk 477, NGC 7130, NGC 5135 and IC...

On the Structure and Morphology of the `Diffuse Ionized Medium' in Star-Forming Galaxies (1998)

Wang, Jing, Heckman, Timothy, Lehnert, Matthew

Deep H$\alpha$ images of a sample of nearby late-type spiral galaxies have been analyzed to characterize the morphology and energetic significance of the ``Diffuse Ionized Medium'' (DIM). We find...

Ultraviolet-Optical observations of the Seyfert 2 Galaxies NGC 7130, NGC 5135 and IC 3639: Implications for the Starburst-AGN Connection (1998)

Delgado, Rosa M. Gonzalez, Heckman, Timothy, Leitherer, Claus, Meurer, Gerhardt, Krolik, Julian, Wilson, Andrew, ...

We present and discuss HST (WFPC2 and FOC) images and UV GHRS spectra plus ground-based near UV through to near IR spectra of three Seyfert 2 nuclei (NGC 7130, NGC 5135 and IC 3639). These galaxies,...

A database for galaxy evolution modeling (1996)

Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...

This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.

A database for galaxy evolution modeling (1996)

Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...

This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.

A database for galaxy evolution modeling (1996)

Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...

This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.

A database for galaxy evolution modeling (1996)

Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...

This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.